AT500508B1 - HIGH-STRENGTH ABRASIVELY SINTERED ALUMINUM ALLOYING AND PRODUCTION METHOD THEREFOR - Google Patents

Description

2 AT 500 508 B1

BACKGROUND OF THE INVENTION Field of the Invention This invention relates to an abrasion-resistant, high-strength sintered aluminum alloy suitable for various kinds of sliding parts such as connecting rods, pistons, and the like, and a method for producing the same. More specifically, this invention relates to an abrasion-resistant high-strength sintered aluminum alloy improved in tensile strength and elongation as well as abrasion resistance, and a production method thereof. 10

Background Art For sintered aluminum parts made using a powder metallurgy process, there has been an increasing demand in recent years because they are not only lightweight, but may also have preferable properties that can not be obtained with cast materials, such as Strength, abrasion resistance and the like. Specifically, in a processed alloy containing a large amount of silicon, only an alloy having a metallographic structure in which the primary silicon grains are coarse is obtained. In contrast, in a sintered aluminum alloy, it has been achieved to obtain a sintered aluminum alloy having a metallographic structure in which the Al-Si alloy phase having fine primary silicon grains dispersed therein and the aluminum solid solution phase having no primary Silicon grains are dispersed in dots, and which has excellent strength and abrasion resistance (see Japanese Patent Application Laid-Open Nos. JPA-H04-365382, JPA-H07-197168, JPA-H07-197163 and JP-A-H07-224341). These sintered aluminum alloys have excellent abrasion resistance. However, they have a thickness of 360 MPa or so, even though molding and heat treatment are performed therewith; and their application is limited and a sintered aluminum alloy with a higher strength should therefore be produced. 30

In short, this is not such a material that has a high degree of tensile strength and elongation properties.

Brief Summary of the Invention 35

In view of the above problems, therefore, it is an object of this invention to provide a novel sintered aluminum alloy having abrasion resistance and at the same time higher tensile strength and high elongation, and a process for producing the same. It is also an object of this invention to provide a sintered aluminum alloy manufacturing method wherein the zinc content of the sintered aluminum alloy does not fluctuate after sintering to obtain a constant mechanical strength and to realize a stable mass production thereof. To achieve these objects, an abrasion-resistant, high-strength sintered aluminum alloy according to one aspect of this invention, by mass, comprises: 3.0 to 10% zinc; 0.5 to 5.0% magnesium; 0.5 to 5.0% copper; 0.1 to 10% hard particles; an unavoidable amount of impurities and aluminum having a metallographic structure comprising: an aluminum alloy matrix in which the hard particles are dispersed; and an intermetallic compound phase precipitated distributed in the aluminum alloy matrix.

A process for producing an abrasion-resistant high-strength sintered aluminum alloy according to one aspect of the invention comprises: preparing a raw material powder comprising, by mass: 3.0 to 10% zinc; 0.5 to 5.0% magnesium; 55 0.5 to 5.0% copper; 0.1 to 10% hard particles; an unavoidable amount of contaminant and balance aluminum by using: an aluminum powder having a particle size of 140 μτη or less; a powder for the hard particles having a particle size of 113 μm or less; and a combination of simple metal powders, combination of binary alloy powders or a combination of a simple metal powder and a binary alloy powder comprising zinc, magnesium and couplers and having a particle size of 74 μm or less; Pressing the raw material powder in a die at a compacting pressure of 200 MPa or more to form a compact having a predetermined shape; Sintering the compact in a non-oxidizing atmosphere so that the compact is heated from 400 ° C to a sintering temperature of 590 to 610 ° C at a temperature elevation rate of 10 ° C per minute or more and the sintering temperature is 10 minutes or more is kept longer before the sintered compact is cooled to room temperature; and performing a heat treatment with the compact after sintering, comprising: heating the compact at a temperature of 460 to 490 ° C and quenching with water so as to dissolve a precipitation phase in the aluminum base of the compact to produce the solid solution; and maintaining the temperature in a range of 110 to 200 ° C for 2 to 28 hours to produce a precipitation phase of the solid solution.

A method for producing a high-strength, wear-resistant sintered aluminum alloy according to another aspect of this invention comprises: preparing a starting material powder comprising, by mass: 3.0 to 10% zinc; 0.5 to 5.0% magnesium; 0.5 to 5.0% copper; 0.1 to 10% hard particles; an unavoidable amount of impurities and balance of aluminum, by using: a simple aluminum powder of at least 15 mass% of the starting material powder; an aluminum alloy powder containing all of zinc containing the raw material powder; and a powder for the hard particles at 0.1 to 10 mass% of the raw material powder; Pressing the raw material powder in a die at a compacting pressure of 200 MPa or more to form a compact having a predetermined shape; Sintering the compact in a non-oxidizing atmosphere at a sintering temperature of 580 to 610 ° C for 10 minutes or more before cooling the sintered compact to room temperature; and performing a heat treatment with the compact after sintering, comprising: heating the compact at a temperature of 460 to 490 ° C and quenching with water so as to dissolve a precipitation phase in the aluminum base of the compact to produce a solid solution; and maintaining the temperature in a range of 110 to 200 ° C for 2 to 28 hours to produce a precipitation phase of the solid solution. 35

According to the above construction, the sintered aluminum alloy of this invention has excellent high tensile strength and elongation as well as high abrasion resistance. In the method of producing a sintered aluminum alloy of this invention, the tensile strength and elongation are improved particularly for the abrasion-resistant sintered aluminum alloys, thereby enabling the use for various types of sliding parts used in vehicles and realizing various sliding parts of small weight ,

The features and advantages of the prior art manufacturing method of this invention will be better understood from the following description of the preferred features of this invention.

DETAILED DESCRIPTION OF THE INVENTION The present inventors have described in Japanese Patent Applications 2003-345001 and 2004-2069547 a manufacturing method of an aluminum alloy having a composition of ASM (American Society for Metals) 7xxx series known as Extra Super Duralumin , proposed and developed by a powder metallurgical process. In this application, an attrition-resistant sintered aluminum alloy having simultaneously high strength is obtained based on the above sintered alloy by adding hard particles to the composition. Moreover, the production method is further improved for preventing the evaporation of zinc and the variation of the zinc content by incorporating the entire amount of zinc in the form of the aluminum alloy and for preventing the lowering of the compressibility of the starting material powder by using at least 15 mass%. a simple aluminum powder in combination with the aluminum alloy powder as the raw material powder.

The features of this invention will now be described, with each component and step of the manufacturing process being explained in detail. It should be noted that in the description of this invention, AI, Zn, Mg, and the like are symbols of the elements used, and that the expression " aluminum parts " as aluminum-based parts or parts composed mainly of aluminum and possibly containing small amounts of other elements should be understood. In addition, the " sintering temperature " the maximum temperature at which compact is sintered, and the sintering time indicates the time period during which the temperature is in the range of the sintering temperature. (1) Raw material powder mixing step

In this step, a raw material powder mixture to be compacted is prepared by mixing the respective powdered starting materials, the details of which are described below. (1) -1 Ingredients of composition 25 < zinc >

Zinc together with magnesium is precipitated in the aluminum matrix in the form of MgZn2 (η-phase) or Al2Mg3Zn3 (T-phase) to increase the strength. When the temperature for sintering is elevated, zinc is melted to give a liquid phase, and this wets the surface of the aluminum particles to eliminate the oxide layer thereon, and is diffused into the aluminum matrix, so that it also accelerates the bonding of the aluminum particles resulting from the diffusion of these, interacting with each other due to such diffusion of zinc. When the content of Zn is below 3 mass%, it is difficult to sufficiently develop the effects described above, with the result that the effect of increasing the strength becomes poor. On the other hand, when the content is more than 10 mass%, the amount of Zn in the sintered mass or the amount of a Zn-based eutectic liquid phase becomes excessively large, with the result that it becomes impossible to maintain the shape of the compact , Moreover, when Zn is excessive or the diffusion of Zn into the Al base is insufficient, the content remains in the Zn-rich phase form 40. Further, Zn volatilizes from the inside of the alloy and thus contaminates the interior of the furnace and is deposited thereon. Accordingly, the content of Zn is preferably in the range of 3 to 10 mass%. ≪ & gt magnesium; 45

Magnesium forms the above-described precipitating compound together with zinc so as to contribute to the increase of the starch. Also, Mg has a low melting point, and when the temperature for carrying out sintering is increased, it generates a liquid phase for eliminating the oxide layer to accelerate the progress of sintering. If the Ge content of Mg is below 0.5 mass%, this makes the above-described effect poor, and if it is more than 5.0 mass%, it increases the amount of the liquid phase to become excessively large which makes it impossible to maintain the shape of the compact. Accordingly, the content of Mg is preferably in the range of 0.5 to 5.0 mass%. 55 5 AT 500 508 B1 < copper >

Copper is dissolved in the aluminum matrix to form a solid solution and precipitate a compound of CuAl2 (Θ-phase), thereby contributing to the increase in strength. It also generates a liquid phase in performing the sintering step and accelerates the progress of sintering. In view of the content of Cu, its effect is not sufficiently achieved if it is less than 0.5 mass%, and if it exceeds 0.5 mass%, copper forms an unnecessary Cu-Zn alloy phase with zinc, which precipitates to a large extent along the grain boundary, causing a decrease in the strength and the elongation. Therefore, the amount of Cu is preferably in the range of 0.5 to 5.0 mass%. < Hard Particles > The metallographic structure of the aluminum alloy matrix composed of the above-described components which does not have hard particles exhibits excellent mechanical properties equal to the general steel materials, so that the tensile strength is 500 MPa or more and the elongation is 4% or more is when the conditions for compacting, sintering, forging and heat treatment are selected appropriately.

In general, the incorporation of a hard phase into an alloy matrix leads to a reduction in the strength and elongation of the alloy. Because the aluminum alloy matrix is formed as a base to an alloy with the starch imparting elements described above, extremely high strength and elongation may be likely to occur in comparison with the conventional abrasion resistant aluminum-silicon sintered alloys besides a small reduction in strength and elongation the addition of the hard particles unfolded. In this invention, moreover, it is advantageous that the kind and amount of the dispersed hard particles can be easily changed according to the sliding properties (especially, the sliding part). Specifically, the hard particles dispersed in the conventional abrasion-resistant sintered aluminum-silicon alloy are primary silicon crystals, and this tends to increase the friction coefficient when the sliding part is made of iron-containing material due to the affinity between iron and silicon , In contrast, in the sintered aluminum alloy of the present invention, it is possible to reduce the friction coefficient and increase the abrasion resistance by selecting a kind of hard particles having low affinity for iron such as chromium boride or the like. The hard particles which can be used in the present invention include silicon carbide, chromium boride, boron carbide and the like. When the content of the hard particles in the sintered aluminum alloy is 0.1 mass% or more, the effect of improving the abrasion resistance is emphasized and if is more than 10 mass%, the strength and elongation are remarkably decreased. Therefore, the content of the hard particles is preferably in the range of 0.1 to 10 mass%. When the hardness of the hard particles is insufficient, the hard particles themselves cause plastic flow, leading to a reduction in abrasion resistance. Accordingly, the Vickers hardness of the hard particles is preferably 600 Hv or more, and more preferably 1000 Hv or more, especially when an Al-Zn alloy powder is used as the starting material. < Sn, Bi, ln > 50

Tin, bismuth and indium have a low melting point and produce a liquid phase in the sintered mass. As a result, they wet the surface of the aluminum particles and eliminate the oxide layer from the surface of the aluminum particles to accelerate the progress of sintering between the Al powder particles without dissolving in aluminum. In addition, due to the surface tension of the liquid phase, the liquid 6 AT 500 508 B1 causes

A shrinkage phase, which contributes to the compression of the resulting mass. Therefore, it is preferable that the above elements are used as a sintering aid together with the above-described elements Zn, Mg and Cu. If the length of the period during which the liquid phase exists is increased, the compression to be written to the liquid phase continues to decrease. When the liquid phase is generated at an early stage of the sintering step so that the liquid phase exists during almost the complete step of sintering, the compaction effect becomes large. In this respect, Sn (melting point: 232 ° C), Bi (melting point: 271 ° C) and In (melting point: 155.4 ° C) are very suitable because they have a low melting point and are hardly dissolved in the main component Al. Moreover, the liquid phase of these low-melting metal components covers the surface of the simple zinc powder or the zinc alloy powder, preventing the evaporation of zinc and fluctuation of the zinc content in the resultant sintered alloy.

Sn, Bi and In, which are used as sintering aids, can be used in the form of a simple metal powder. When these elements are used as main components and form a eutectic compound causing production of a eutectic liquid phase with these main components, their melting point is much lower than that of the single substance. Therefore, the generation of this eutectic compound is still preferred. This eutectic liquid phase may be one generated by combining the main component (Sn, Bi, In) and another element, or may be one generated by combining the main component and an intermetallic compound containing the main component and another metal covered. Also, there is a compound due to a eutectic reaction which can be found in a part of the monotactic compounds, and it is also possible to use such a monotactic compound which causes the production of a liquid eutectic phase comprising Sn, Bi or In , As elements constituting the eutectic liquid phase, such as those with Sn, there are Ag, Au, Ce, Cu, La, Li, Mg, Pb, Pt, Tl, Zn, and the like. As the elements, the eutectic liquid phase such as Bi There are Ag, Au, Ca, Cd, Ce, Co, Cu, Ga, K, Li, Mg, Mn, Na, Pb, Rh, S, Se, Sn, Te, Tl, Zn and the like as elements , which form such a eutectic liquid phase as described above with In, there are Ag, Au, Ca, Cd. Cu, Ga, Sb, Te, Zn and the like. Although these respective groups of elements are an example of a simple two-elemental or binary system, the same effect can be obtained even in a case of a three-elemental or ternary system, a four-elementary or quaternary system or a multi-elemental system System as long as the resulting eutectic liquid phase likewise has Sn, Bi 35 or In as a main component and has a composition causing the production of a eutectic liquid phase containing the main component. In view of Pb and Cd of the above elements, it is preferable to dispense with their use in view of the toxicity, though these elements also cause the production of a liquid eutectic phase with Sn, Bi or In. 40

When the above-described point of view is also taken into consideration, as a multielemental system of the eutectic alloy containing Sn, Bi or In as a main component, a lead-free solder whose development has been promoted in recent years can be preferably used. As the lead-free solder, masses of the Sn-Zn system, Sn-Bi system, Sn-45Zn-Bi system, Sn-Ag-Bi system or the like can be given, and lead-free solder materials prepared by adding a small amount of a metal element such as In, Cu, Ni, Sb, Ga, Ge or the like to the above system have also been proposed. A part of these has actually been put to practical use, and it is preferable to use those unleaded solder materials that are commercially available because they are easy to obtain. 50

The sintering aid unfolds with the addition of 0.01 mass% or more a considerable compaction effect. When used in a large amount, Sn, Bi and In are precipitated as a grain boundary, causing the decrease in strength because they are not dissolved with Al. Therefore, their use should be limited to 0.5% by mass or less to a maximum of 55%. The addition in an amount of 0.5 mass% or more causes the reduction of the starch due to the precipitation of Sn, Bi and In at the grain interface to be larger than the effect of compaction due to the above-described Shrinkage of the liquid phase, which leads to a further reduction in strength. 5 (1) -2 form of powder A. Use of a simple zinc powder

With respect to the above-described elements Zn, Mg and Cu, there is no inconvenience when added to the zinc powder when used as a simple element powder, alloy powder of two or more types of these elements or as a powder mixture thereof. However, in order for the elements described above to act uniformly in the base, it is necessary to uniformly disperse the respective constituent elements in the matrix. For this reason, it is recommended that such constituent elements as described later be added in the form of fine powders whose particle size is 200 mesh (74 / vm) or less. When so added, the simple element powder or alloy powder is melted as the temperature is raised during sintering, and changes to a liquid phase to wet the surface of the aluminum powder to eliminate the oxide layer thereon. They are then diffused into the aluminum matrix and additionally accelerate the bonding between the aluminum powder particles due to such diffusion. When the particle size of the simple element powder or the alloy powder exceeds 200 mesh, local segregation occurs to inhibit the uniform diffusion of the components. On the contrary, when the simple aluminum powder is also as fine as above, the flowability of the raw material powder mixture is lowered. With respect to the aluminum powder, therefore, it is preferable to use them in a larger particle size than the powders for the above-described elements. When the particle size exceeds 100 mesh (140 pm), the above-described components are difficult to diffuse in the aluminum particles, leading to segregation. B. Use of aluminum alloy powder with the total amount of zinc

Zinc is an element that can volatilize at high temperature. Therefore, when zinc in the form of an aluminum alloy powder is added by having the whole amount of Zn with aluminum, the amount of Zn remaining by the volatilization of Zn becomes more stable than in the case where Zn is added as a simple zinc powder , As a result, the degree of fluctuation among the products becomes small. However, the incorporation of Zn causes hardening in the aluminum alloy powder to lower the compressibility of the powder. Therefore, when Zn is formed into the alloy with the whole amount of aluminum, the compressibility of the raw material powder decreases. Therefore, it is necessary to restrict the use of the aluminum alloy powder with zinc to only a part of the total powder for aluminum 45 and to mix soft aluminum powder into the aluminum alloy powder by incorporating the entire amount of Zn to increase the compressibility of the raw material powder. In order to sufficiently achieve this purpose, the amount of the simple aluminum powder used must be necessarily set to 15 mass% of the total raw material powder or more. 50

When the aluminum alloy powder comprising Zn has a composition causing the production of an Al-Zn liquid phase at a low temperature, Zn may volatilize from this Al-Zn liquid phase. Therefore, it is preferable that the aluminum alloy powder has a composition that causes the production of the Al-Zn-liquid phase at as high a temperature as possible, that is, as high as possible. only at a temperature of 8 AT 500 508 B1

Final stage of the sintering step. In addition, when an aluminum alloy powder having a large amount of Zn is used, it causes a proportionate increase in the amount of a simple aluminum powder, with the result that Zn dispersed in the aluminum alloy sintered matrix can not be uniform. This causes the occurrence of the fluctuation in the values of the obtained mechanical properties. In view of this, it is preferable that the content of Zn in the aluminum alloy powder is 30 mass% or less. On the other hand, when the Zn content in the aluminum alloy powder falls below 10 mass%, the difference in zinc concentration from the simple aluminum powder becomes small, with the result that Zn has difficulty diffusing and uniform diffusion Opposite is suppressed. Accordingly, it is preferable that the content of Zn in the aluminum alloy powder is in the range of about 10 to 30 mass%. C. Forms of Mg and Cu 15

The use of the aluminum alloy powder having a composition causing the production of the Al-Zn liquid phase only at a high temperature is preferable for preventing the volatilization of zinc, but is disadvantageous because of the uniform diffusion of the components. Cu and Mg are used together with Zn to allow the uniform diffusion of Zn into the matrix described above. Cu and Mg, in the method in which the temperature is raised during sintering, cause the production of a Cu-Zn liquid phase or Mg-Zn liquid phase together with Zn powder or Zn in the aluminum alloy powder. These liquid phases are immediately solidified by absorbing their components in the aluminum powder or aluminum alloy powder, and the liquefaction and solidification are repeated so that the uniformity of the components is fast. In addition, the liquid phase is solidified at this time so fast that no problems with the volatilization of Zn occur. The elements Cu and Mg each having the above-described effect may be added in the form of a simple metal powder, an alloy powder of both elements or an alloy powder 30 with aluminum, and no obstacle occurs in any of the above cases. When the aluminum alloy powder containing Zn simultaneously contains Cu at a content of 10 mass% or less, the effects described above become more apparent. When the amount of Cu added to the aluminum alloy powder exceeds 10 mass% of the aluminum powder, the temperature at which Cu produces a liquid phase together with 35 Zn shifts to the high-temperature side, and the addition of more than 10 mass% is thus disadvantageous in view of the uniform diffusion of the components. D. Forming Sn, Bi and In When Sn, Bi or In are used as a sintering aid, they may be added in the form of a simple metal powder, eutectic alloy powder or monotectic alloy powder which causes generation of a eutectic liquid phase with these main components. 45 E. Powdered material for hard particles

As means for dispersing the hard particles into the aluminum alloy matrix, it is appropriate to add a powdered material for the hard particles. When the powdered material reacts with the main component of the matrix, Al, it becomes difficult to control the amount and thus the range of particle size of the hard particles dispersed in the aluminum alloy matrix after sintering. It is preferred that the added powder is produced as hard particles of a material which does not react with aluminum. For the hard particles described above, silicon carbide, chromium boride, boron carbide and the like are preferred materials because they are extremely hard and do not react with aluminum. Because the aluminum alloy matrix is somewhat soft, the hard particles derived from a powder of extremely hard material are embedded in the aluminum alloy matrix during the sliding operation so as to suppress the abrasion of the sliding part and at the same time suppress the plastic Flow of the aluminum alloy matrix, which contributes to the improvement of abrasion resistance. Even if they once fall off the aluminum alloy matrix during the sliding operation, they are re-embedded in the soft aluminum alloy matrix, so that the effect of preventing the plastic flow of the matrix is repeatedly exhibited. io (1) -3 size of the powder

In order for the respective constituent elements to deploy their roles simultaneously in the matrix, it is necessary to evenly diffuse these constituent elements in the matrix. For this purpose, it is preferable that each of these constituent elements is added in the form of fine powder 15 whose particle size is 74 μηi (200 mesh) or less (ie, 200 mesh minus sieve or powder having a particle size passing through a comb sieve with 200 mesh) with the exception of the simple aluminum powder. The simple metal powder or alloy powder, when the temperature is raised during sintering, is melted to obtain a liquid phase which wets the surface of the aluminum powder for eliminating the oxide layer and which is diffused into the aluminum matrix, and at the same time bond between them To accelerate aluminum powder particles due to diffusion. When the particle size of the simple metal powder or alloy powder exceeds 200 mesh, local segregation occurs and uniform diffusion of constituent elements does not occur. 25

However, if the aluminum powder is also a fine powder, the flowability of the raw material powder becomes poor. Therefore, it is suitable to use a powder for aluminum whose particle size is larger than that of the respective constituent element powder described above. Specifically, it is preferable to use a powder for aluminum whose particle size is 140 μτη (100 mesh) or less (i.e., 100 mesh minus sieve or powder whose particles have a size passing through a 100 mesh sieve). When the size of 100 mesh is exceeded, each constituent element has the difficulty of diffusing to the center of the powder and the component is segregated. Therefore, this should be avoided. 35

Because the powdered material for the hard particles almost does not react with the matrix, it is to be dispersed into the aluminum alloy matrix and left to be added. As a result, the size of the starting powder used for hard particles can be determined as that of the hard particles dispersed in the aluminum alloy matrix. The particle size of the hard particles dispersed in the aluminum alloy matrix is preferably 1 to 100 μm on the average. If the hard particles are less than 1 μm, they easily flow with the matrix as the matrix flows plastically, and it is therefore difficult to avoid the plastic flow of the matrix. When the hard particles are larger than 100 μm, abrasion is easily caused on the sliding part during the sliding operation depending on the sliding conditions. In order to uniformly disperse the hard particles having an average particle size in the above-mentioned range in the aluminum alloy matrix, a powder of a material that does not react with aluminum, having a size of 113 / vm (125 mesh) or less (ie, 125 mesh minus) is preferable. Sieve or powder whose particles have a size passing through a screen of 125 mesh). 50 (2) compacting step

In this step, the raw material powder prepared by the above-described raw material powder mixing step is filled in a nozzle having a predetermined configuration, 55, and the powder is then compactly molded by compression under a compacting pressure of 10 MPa 500 508 B1 of 200 MPa or more. As a result, a compact having a density ratio of 90% or more is obtained. When the compacting pressure is below 200 MPa, the density of the compact becomes low, and even after the compact is passed through the subsequent sintering step and molding step, pores remain at 2 vol% or more. This results in no high strength and elongation being imparted. Such insufficient compacting is also not preferable for the reason that the dimensional change during sintering becomes large. The higher the compaction pressure, the higher the density of the obtained compact. Therefore, a high compaction pressure is preferred. When the compacting pressure is 400 MPa or more, a compact whose density ratio is 95% or more is obtained, and this is suitable. In addition, a compaction pressure of more than 500 MPa easily causes the adhesion of the aluminum powder to the nozzle, and therefore, it is undesirable. (3) Sintering Step 15 When a large amount of the above-mentioned relevant liquid phase is generated during sintering, the amount of shrinkage of the sintered mass becomes large, with the result that the dimensional precision becomes poor. Because zinc contained as an ingredient is a low melting point element and therefore is easily volatilized during the sintering step, the amount of zinc dissolved in the base to produce the solid solution is reduced by volatilization. resulting in that no desired value of the strength and elongation is achieved. At the same time, zinc contaminates the sintering atmosphere and in some cases it is deposited inside the furnace, causing the problem with the working environment. In order to avoid such adverse effects, it is then advisable, when using a simple zinc powder, that the elevation of the temperature up to the sintering temperature is carried out at a high rate.

Therefore, in sintering the compact obtained in the above-described compacting step, it is recommended that, during the temperature rise from room temperature to sintering temperature, heating in the temperature range of at least 400 ° C, which is near the melting point of zinc, to the sintering temperature quickly at a temperature elevation rate of 10 ° C per minute or more in order to suppress the volatilization of the respective constituent elements. Moreover, sintering of the compact is performed by heating the compact at a sintering temperature of 580 to 610 ° C (using the aluminum alloy powder with zinc) or 590 to 610 ° C (without Zn-containing aluminum alloy powder) for a sintering time of 10 minutes or more, while suppressing the excessive diminution of dimensional precision due to the generation of a liquid phase and achieving uniform diffusion of constituent elements. If the temperature increase rate for raising to sintering temperature is lower than 10 ° C per minute, the problem of volatilization of zinc becomes remarkable. If the sintering temperature exceeds 40 610 ° C, the problems of volatilization of zinc and over-shrinkage due to the liquid phase become remarkable and, in this case, the crystal grains also grow and become large, causing a decrease in the strength. It is necessary for the uniform formation of the solid solution with the respective constituent elements in the Al base that the sintering temperature be 580 ° C (using (Zn-45-containing Al alloy powder), 590 ° C (without using Zn-45). Al-alloy powder) or more, and that this sintering time is 10 minutes or more When the sintering conditions fall outside these ranges, the diffusion of the respective components into the Al base becomes insufficient, resulting in a decrease in the strength As described above, the sintered compact is then cooled, and the cooling rate is better, although not particularly limited, when the cooling rate is low, in particular In the high temperature range (450 ° C or more), the increase of the size of the crystal grains decreases, in addition, the component drops which is supersaturated in the course of the cooling, sometimes along the grain interface, causing a reduction in strength and elongation. Also, the region where the supersaturated component precipitates sometimes absorbs in the matrix by performing a subsequent heat treatment (solution treatment) to form pores causing the deterioration of the strength and elongation. Therefore, it is better to cool in the high tempera ture range at the highest possible rate. In particular, in the temperature range of 450 ° C or more, it is preferable that the sintered compact is cooled at a rate of -10 ° C / min.

With respect to the sintering atmosphere, a non-oxidizing one is suitable. Among the various non-oxidizing gases, an atmosphere of nitrogen gas in which the dew point is -40eC or less is most suitable. The dew point is an indicator indicating the amount of water in the gas atmosphere, and a large amount of water, which is substantially a large amount of oxygen, hinders the progress of the sintering process because Al can bind with oxygen, with prevention the compression of the mass. Because nitrogen gas is also inexpensive and safe compared with other non-oxidizing gases, the nitrogen gas atmosphere whose dew point is specified as above is preferable.

According to the above sintering, the constituent elements are uniformly dissolved in the Al matrix to give a solid solution by liquid phase sintering, and a sintered compact in which the density ratio is 90% or more and the pores are closed pores may be obtained , (4) Heat treatment step (T6 treatment) The heat treatment step (T6 treatment according to the regulation of JIS H0001) in the production process of this invention comprises a solution treatment and an aging precipitation treatment. In the solution treatment, a precipitation phase in the Al base is uniformly dissolved in the Al base to form a solid solution by heating at a temperature of 460 to 490 ° C, and the resulting mass is then quenched with water to obtain a supersaturated one solid solution. In the aging precipitation treatment, the resulting mass after the solution treatment is maintained at a temperature of 110 to 200 ° C for 2 to 28 hours to precipitate the supersaturated solid solution and form the precipitation phase dispersed in the Al base. When the temperature for the solution treatment is below 460 ° C, the precipitated components do not uniformly form a solid solution in the Al matrix. On the other hand, when the temperature exceeds 490 ° C, although this effect is almost unchanged, a liquid phase is generated at a temperature of more than 500 ° C to generate pores. In view of the aging treatment, when the temperature is below 110 ° C or the treatment time does not reach 2 hours, a sufficient amount of the precipitated Verbin-40 fertil is not obtained, whereas when the temperature exceeds 200 ° C or the treatment time is 28 hours, the precipitated compound grows and becomes excessively large, resulting in the reduction of the starch. The duration of the aging treatment is about 2 to 28 hours. The temperature and the time period can be suitably set within the above-described ranges according to the required property. By conducting the above-described heat treatment, the metallographic structure in which intermetallic compounds such as MgZn 2 (η phase), Al 2 Mg 3 Zn 3 (T phase), CuAl 2 (O phase) precipitate and are dispersed in the aluminum alloy matrix is formed Achieving the improvement of mechanical properties. Thus, the high-strength abrasion-resistant sintered aluminum alloy obtained by the above-described steps is defined such that the density ratio is 90% or more and exhibits such excellent characteristic as a tensile strength of 450 MPa as well as elongation and abrasion resistance. which are the same as with the conventional material. Moreover, it is possible to further perform the mechanical property by 55 an additional step of performing a forming step between the sintering step and the heat treatment step. (5) Shaping step causing plastic flow under pressure 5 At this step, sintered shaped aluminum parts having high tensile strength and high elongation can be obtained by subjecting the sintered mass obtained by the above-described steps to heat treatment and with a density ratio of 90%. a cold-forming step in which they are molded at room temperature at a stamper ratio of 3 to 40%, or subjected to a hot-forming step of being molded at a temperature of 100-450 ° C at a stiffening ratio of 3 to 70% Obtaining a sintered, formed aluminum part having an increased density ratio of 98% or more. The resulting part has a high tensile strength and elongation.

In general, it is known to increase the density by performing the shaping treatment. With a porous material, however, simply increasing the density merely results in the pores being closed and no metallic bond being formed on the pore walls. As a result, cracks occur in the surface of the material during molding, or the voids remain as defects within the product, thereby not increasing the strength and elongation. To obtain a high degree of strength and deh-20 nung it is therefore necessary not only to close the pores, but also to form a metallic bond. In order to obtain this metallic bond, molding is generally performed by two-divided sub-steps, one of which is a sub-step for carrying out the densification of the relevant material and the other step is a deforming sub-step for obtaining a metallic compound by deforming the compacted material.

According to the invention, in order to obtain a metallic bond, a technique of performing upset forging is employed, which involves applying a pressure from above and below to the sintered porous material obtained as above to compress in the direction of height to close the Pores and also for deforming the compressed material towards the space provided on the lateral side of the material, for causing a plastic flow of the material in the direction crossing the direction in which the pressure is imposed, thereby forcibly the material bonding of the original pore regions is formed (ie, the region where the pore is closed, although no metallic bonding occurs), while the metallic bond is formed in these pore regions. Accordingly, the molding step of this invention involves a single operation in which the operations of the two sub-steps, which are conventionally performed, are mixed. In the context of the chamfer molding, the chamfering ratio is determined as the ratio of the difference in printing direction between the dimensions before and after the molding of the material with respect to the dimension before molding the material. Here it should be noted that the importance of the shaping step of this invention is to cause the lateral plastic flow of the material under pressure. If the anvil deformation described above is the main work of the forming step operation, this is acceptable and no hindrance exists even though the process of the forming step also occurs locally or partially as forward or backward extrusion on the material. For the forming operation according to this invention may include a technique in which the material is extruded locally. Moreover, the operation in which the area of the material is reduced by means of a nozzle, such as molding with forward and backward extrusion and the like, may also be included in the process of the forming step, because the pressurization in this process works in the radial direction and the direction in which the material is deformed is along the extrusion direction or a direction that intersects the pressing directions at right angles. Therefore, the above working technique is also included within the scope of this invention. By carrying out the above molding operation for compressing and plastic matter flow as described above, it is also possible, in addition to the above-described 13 AT 500 508 B1

Effect to obtain an effect which makes the crystal grains grown during sintering fine, as well as to break the precipitate, whereby the strength and elongation are more increased. 5 For cold forging, it is necessary to forge so that the upset ratio is 3 to 40%. If the staking ratio is less than 3%, deformation will only occur locally if the diameter after forging is equal to or greater than that before forging, with the result that the amount of residual pores is increased, thereby increasing the strength and the elongation can not be increased. When forging is performed with a nozzle whose diameter is small, such as forward extrusion forging, an upsetting ratio of 3% or more is required for the reason mentioned above. When the staking ratio is 10% or more, the forged mass density ratio can be easily set to 98% or more. Therefore, this adjustment is preferred. On the other hand, if the swage ratio exceeds 40%, cracking of the forged mass 15 may occur. When performing the cold forging operation, when the upset forging is performed so that the terminal end portions of the material that has laterally expanded during forging come into full contact with the inner wall of the die at the completion of the forging, the precision of the dimension and the shape of the products and defects are difficult to remain on the outermost surface. Therefore, such a type of upset forging is preferred.

In hot forging, when the heating of the material (sintered mass) is within a range of 100 to 450 ° C, preferably 200 to 400 ° C, forging is allowed at an upsetting ratio within a range of 3 to 70%. When the heating temperature for the material (sintered mass) is below 100 ° C, almost no useful change is achieved as compared with the cold forging. That the deformability of the material is still poor and it is therefore difficult to increase the upsetting ratio. When the heating temperature of the material (sintered mass) is 200 ° C or more, the material softens and the deformability increases. As a result, it is possible to reduce the forging pressure for performing the hot forging at a desired value for the upset ratio. Therefore, such a temperature range is preferable. On the other hand, if the heating temperature exceeds 450 ° C, the adhesion between the nozzle and the material (sintered mass) remarkably occurs. Therefore, the upper limit must be set to 450 ° C maximum, and preferably 400 ° C. Even in the above-described suitable temperature range, clogging can occur when the creep rate exceeds 70%. Also, in hot forging, defects have difficulty remaining on the uppermost surface when the upset forging is made so that the terminal end portions of the material which laterally expanded during forging contact the inner wall of the nozzle at the completion of the forging operation. Therefore, such a type of upset forging is preferred.

The abrasion-resistant high-strength sintered and forged aluminum alloy obtained by the above-described method has a density ratio of 98% or more as apparent from the following examples, and is improved to have a tensile strength of 500 MPa or more and has an elongation of 2% or more. Therefore, it exhibits high mechanical properties that can not be expected from the conventional material, as well as excellent abrasion resistance.

Examples 50 (Example 1) For each example, the raw material powder mixing step, compacting step, sintering step, forging step and heat treatment step were sequentially performed 55 for producing and evaluating five types of sintered aluminum alloy samples 14 AT 500 508 B1 having a total composition shown in Table 2 Specifically, in the raw material powder mixing step, aluminum powder having a particle size of 100 mesh " minus screen ", zinc powder, magnesium powder, copper powder, tin powder, bismuth powder, indium powder, lead-free solder powder of 8 mass% tin, 3 mass% of Bi and Residue Sn, each having a particle size of 250 mesh minus sieve; Silicon carbide powder, chromium boride powder and boron carbide powder, each having a particle size of 125 mesh minus sieve, prepared to produce a raw material powder by mixing and mixing these powders according to the mixing ratio shown in Table 1. In the compacting step, after adjusting the compacting pressure 300 MPa the raw material powder to form compacts with columnar shape with dimensions of Φ40 mm x 28 mm for measuring the mechanical property. In the sintering step, the compact was heated in a nitrogen gas atmosphere by raising the heating temperature within a range of 400 ° C to the sintering temperature of 600 ° C at a temperature raising rate of 15 10 ° C / min, and sintered by holding at the sintering temperature for 20 minutes. Thereafter, the compact was cooled from the sintering temperature to 450 ° C at a cooling rate of -20 ° C / min. In the forging step, the sintered compact thus obtained was heated at 400 ° C and placed in a nozzle at the same temperature to perform hot forging at a staggering ratio of 40%. In the heat treatment step, the forged compact was heated at 470 ° C to conduct the solution treatment, and was then held at 130 ° C for 24 hours to carry out the aging precipitation treatment.

As conventional material, aluminum powder and aluminum-silicon alloy powder of 20 mass% Si and balance Al each having a particle size of 100 mesh minus sieve to-25, nickel powder, copper-nickel alloy powder of 4 mass% Ni, were used and balance Cu and aluminum-magnesium alloy powder with 50 mass% Mg and balance aluminum, each having a particle size of 250 mesh minus sieve, prepared to produce a raw material powder by mixing and mixing these powders according to the mixing ratio shown in Table 1 In the compacting step, the compacting pressure was set to 30,200 MPa, and in the sintering step, the compact was heated in a nitrogen gas atmosphere by raising the heating temperature within a range of 400 ° C to the sintering temperature of 550 ° C at a temperature elevation rate of 10 ° C / min, and the sintering temperature was 20 minutes before cooling from the sintering temperature to 450 ° C at he kept cooling rate of -20 ° C / min. In the forging step, the heating temperatures of the sintered compact and the die were 450 ° C and the staking ratio was 40%. In the heat treatment step, the temperature for the solution treatment was 470eC and the aging precipitation was carried out at 130 ° C for 24 hours to produce an alloy described in the document of JPA-H07-224341. In the preparation of each sample, the density ratio was measured for each green compact after the compacting step, the sintered compact after the sintering step and the forged compact after the forging step. The results are shown in Table 3. For the evaluation of the obtained samples A01 to A34, five column pieces of Φ40 mm x 28 mm were processed into a tensile test piece and the tensile test was conducted therewith to measure the tensile strength and elongation. The result is shown as an average in Table 3. The other two columnar pieces were each cut into an abrasion test piece having a pillar shape of Φ7.98 mm × 20 mm, a slip test was conducted thereon on a pin-on-disc abrasion resistance test machine at a sliding speed of 5 m / sec for 30 minutes an inverse of S45C heat treated material was used under constant load and machine oil feed. If a drastic change in the dynamic friction coefficient during the slip test was not observed, the test piece was replaced with another and the load was increased by 5 MPa each time. The load at which a drastic increase in the dynamic friction coefficient was observed was determined as the covering pressure (critical bearing pressure). The results 55 are summarized in Table 3.

Table 1 cji Sample Blend Ratio Mass% Nr- Al-Zn-Mg-Cu Powder Aging Particle Low Melting Metal Powder Powder Powder Powder Powder Type Kind A01 Balance 5.5 2.5 1.5 B4C Powder 0.0 Sn Powder 0.1 Ά02 Balance 5.5 2.5 1.5 B4C powder 0.1 Sn powder 0.1 A03 balance 5.5 2.5 1.5 B4C powder 0.5 Sn powder 0.1 A04 balance 5.5 2.5 1.5 B4C powder 1.0 Sn powder 0.1 A05 balance 5.5 2.5 1.5 B4C powder 2.5 Sn powder 0.1 A06 balance 5.5 2.5 1 , 5 B4C powder 5.0 Sn powder 0.1 A07 balance 5.5 2.5 1.5 B4C powder 10.0 Sn powder 0.1 A08 balance 5.5 2.5 1.5 B4C Powder 15.0 Sn powder 0.1 A09 balance 2.0 2.5 1.5 B4C powder 5.0 Sn powder 0.1 A10 balance 3.0 2.5 1.5 B4C powder 5.0 Sn powder 0.1 A06 balance 5.5 2.5 1-5 B4C powder 5.0 Sn powder 0.1 All balance 10.0 2.5 1.5 B4C powder 5.0 Sn powder 0 , 1 A12 balance 15.0 2.5 1.5 B4C powder 5.0 Sn powder 0.1 A13 balance 5.5 0.1 1.5 B4C powder 5.0 Sn powder 0.1 A14 balance 5.5 0.5 1.5 B4C powder 5.0 Sn powder 0.1 A15 balance 5.5 1.0 1.5 B4C powder 5.0 Sn powder 0.1 A06 balance 5.5 2.5 1.5 B4C powder 5.0 Sn powder 0.1 A16 balance 5.5 5.0 1.5 B4C powder 5.0 Sn powder 0.1 A17 balance 5.5 7.0 1.0 , 5 B4C powder 5.0 Sn powder 0.1 A18 balance 5.5 2.5 0.1 B4C powder 5.0 Sn powder 0.1 AT 500 508 σι

Table 1 (continued) Sample Mix ratio Mass% # Al-. Zn-Mg-Cu Powder Hardening Particle Low Melting Metal Powder Powder Powder Powder Powder Kind Type A19 Balance 5.5 2.5 0.5 B4C Powder 5.0 Sn Powder 0.1 A06 Balance 5.5 2.5 1.5 B4C Powder 5.0 Sn powder 0.1 A2 0 balance 5.5 2.5 2.5 B4C powder 5.0 Sn powder 0.1 A21 balance 5.5 2.5 5.0 B4C powder 5 , 0 Sn powder 0.1 A22 balance 5.5 2.5 7.0 B4C powder 5.0 Sn powder 0.1 A06 balance 5.5 2.5 1.5 B4C powder 5.0 Sn Powder 0.1 A2 3 balance 5.5 2.5 1.5 B4C powder 5.0 Sn powder 0.1 A24 balance 5.5 2.5 1.5 B4C powder 5.0 Sn powder 0, 1 A25 balance 5.5 2.5 1.5 B4C powder 5.0 Sn powder 0.0 A26 balance 5.5 2.5 1.5 B4C powder 5.0 Sn powder 0.01 A27 balance 5 , 5 2.5 1.5 B4C powder 5.0 Sn powder 0.05 A06 balance 5.5 2.5 1.5 B4C powder 5.0 Sn powder 0.1 A28 balance 5.5 2, 5 1.5 B4C powder 5.0 Sn powder 0.5 A29 balance 5.5 2.5 1.5 B4C powder 5.0 Sn powder 0.7 A06 balance 5.5 2.5 1.5 B4C powder 5.0 Sn powder 0.1 A30 balance 5.5 2.5 1.5 B4C powder 5.0 Bi powder 0.1 A31 balance 5.5 2.5 1.5 B4C powder 5 , 0 in powder 0.1 A3 2 remainder 5.5 2.5 1.5 B4C powder 5.0 Sn-8Zn-3Bi powder 0.1 A3 3 Al-20Si powder: 75%, Cu-4Ni powder: 4.2%, Al-50Mg powder: 1%, Al powder: remainder AT 500 508 B1

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Table 2 Sample Overall Composition Mass * # Al Zn Mg Cu Hard Particle Other Type Type A01 Balance 5.5 2.5 1.5 b4c 0.0 Sn 0.1 A02 Balance 5.5 2.5 1.5 b4c 0, 1 Sn 0.1 A03 balance 5.5 2.5 1.5 b4c, 0.5 Sn 0.1 A04 balance 5.5 2.5 1.5 b4c 1.0 Sn 0.1 A05 balance 5.5 2 , 5 1.5 b4c 2.5 Sn 0.1 A06 balance 5.5 2.5 1.5 b4c 5.0 Sn 0.1 A07 balance 5.5 2.5 1.5 b4c 10.0 Sn 0, 1 A08 balance 5.5 2.5 1.5 b4c 15.0 Sn 0.1 A09 balance 2.0 2.5 1.5 b4c 5.0 Sn 0.1 A10 balance 3.0 2.5 1.5 b4c 5.0 Sn 0.1 A06 balance 5.5 2.5 1.5 b4c 5.0 Sn 0.1 all balance 10.0 2.5 1.5 b4c 5.0 Sn 0.1 A12 balance 15, 0 2.5 1.5 b4c 5.0 Sn 0.1 A13 balance 5.5 0.1 1.5 b4c 5.0 Sn 0.1 A14 balance 5.5 0.5 1.5 b4c 5.0 Sn .0.1 A15 balance 5.5 1.0 1.5 b4c 5.0 Sn 0.1 A06 balance 5.5 2.5 1.5 b4c 5.0 Sn 0.1 A16 balance 5.5 5.0 1.5 b4c 5.0 Sn 0.1 A17 residue 5.5 7.0 1.5 b4c 5.0 Sn 0.1 A18 residue 5.5 2.5 0.1 b4c 5.0 Sn 0.1 AT 500 508 B1

Table 2 (continued) Sample Total Composition Mass% No. Al Zn Mg Cu Hard Particle Other species Type A19 Residue 5.5 2.5 2.5 b4c 5.0 Sn 0.1 A06 Balance 5.5 2.5 1.5 b4c 5.0 Sn 0.1 A20 balance 5.5 2.5 2.5 b4c 5.0 Sn 0.1 A21 balance 5.5 2.5 5.0 b4c 5.0 Sn 0.1 A22 balance 5, 5 2.5 7.0 b4c 5.0 Sn 0.1 A06 balance 5.5 2.5 1.5 b4c 5.0 Sn 0.1 A23 balance 5.5 2.5 1.5 b4c 5.0 Sn 0.1 A24 residue 5.5 2.5 1.5 b4c 5.0 Sn 0.1 A25 residue 5.5 2.5 1.5 b4c 5.0 Sn 0.0 A26 residue 5.5 2.5 1 , 5 b4c 5.0 Sn 0.01 A27 balance 5.5 2.5 1.5 b4c 5.0 Sn 0.05 A06 residue 5.5 2.5 1.5 b4c 5.0 Sn 0.1 A28 residue 5.5 2.5 1.5 b4c 5.0 Sn 0.5 A29 balance 5.5 2.5 1.5 b4c 5.0 Sn 0.7 A06 balance 5.5 2.5 1.5 b4c 5, 0 Sn 0.1 A30 residue 5.5 2.5 1.5 b4c 5.0 Bi 0.1 A31 residue 5.5 2.5 1.5 b4c 5.0 In 0.1 A3 2 residue 5.51 2 , 5 1.5 b4c 5.0 Sn 0.09 1 Bi 1 0.003 A33 Al-15%, Si-4%, Cu-0.17%, Ni-0.5% Mg AT 500 508 B1

Table 3 < θ Sample Density Ratio% Evaluation Comments No. Green Sintered Forged Tensile Strain Elongation Compact Compact Compact Compactness, MPa% Pressure, MPa A01 93.6 97.9 99.3 530 4.2 20 A02 93.0 97.0 99.3 530 4.0 30 A03 93.0 97.0 99.3 530 4.0 35 A04 92.5 96.5 99.3 520 3.5 40 A05 92.5 96.5 99, 3 520 3.5 40 A06 92.5 96.5 99.3 520 3.5 40 A07 90.0 96.0 99.3 500 2.8 40 A08 88.1 94.0 99.3 480 1.6 40 Great abrasion on the contrary A09 92.5 90.1 99.5 461 4.3 20 A10 92.5 94.8 99.3 503 3.6 30 A06 92.5 96.5 99.3 520 3.5 40 All 92.5 95.4 99.4 481 2.1 35. A12 92.5 - - - - - Melting of the sintered mass A13 92.5 93.2 99.5 473 4.4 20 A14 92.5 94.8 99.5 501 4.2 35 Al 5 92.5 96.0 99.3 510 4.0 40 A06 92.5 96.5 99.3 520 3.5 40 A16 92.5 95.4 99.4 507 1.8 35 Deformation of the sintered mass A17 92.5 - - - - - 'A18 92.5 94.7 99.3 481 4.1 20 AT 500 508 B1

Oil Table 3 (continued) Sample No. Density Ratio% Evaluation Remarks Green Compact Sintered Compact Forged Compact Tensile strength, MPa Elongation% Coverage pressure, MPa A19 92.5 94.9 99.4 508 3.8 35 A06 92.5 96, 5 99.3 520 3.5 40 A20 92.5 96.2 99.5 503 2.4 40 A21 92.6 95.8 99.4 498 1.6 30 A22 92.7 92.1 99.4 472 0.3 - elongation worsens A06 92.5 96.5 99.3 520 3.5 40 A23 91.8 96.3 99.4 525 3.2 45 A24 93.2 97.2 99.3 525 3, 8 50 A25 92.5 90.4 99.3 470 2.6 30 A26 92.5 96.0 99.3 515 3.0 40 A27 92.5 96.5 99.3 520 3.2 40 A06 92, 5 96.5 99.3 520 3.5 40 A28 92.5 96.5 99.3 500 3.0 40 A29 92.5 94.4 99.3 470 1.8 30 A06 92.5 96.5 99 , 3 520 3.5 40 A30 92.5 96.5 99.3 523 3.3 40 A31 92.5 96.5 99.3 512 3.8 40 A32 92.5 96.5 99.3 521 3, 3 40 A33 85.0 87.0 99.8 360 2.5 50 ho o AT 500 508 B1 21 AT 500 508 B1

Comparing the samples of the numbers A01-A08, the effect of the hard particles with the addition amount is examined. From the results, it is understood that the sample No. A01 containing no hard particles exhibits high tensile strength and elongation, but that the coating pressure is small, which means that the material has a low abrasion resistance to -5. Even with such a material, the abrasion resistance by the hard parts can be improved in an amount of 0.1 mass% or more, so that the coating pressure increases to 30 MPa or more, while the drop of the tensile strength can be suppressed to a small extent , In particular, the addition of 1.0 mass% or more leads to a high abrasion resistance. On the other hand, when the amount of the hard particles increases, the elongation tends to be little reduced, but it is still possible to develop a sufficient elongation with an amount of 10 mass% or more of the hard particles. If the amount of the hard particles exceeds 10 mass%, the reduction of the elongation becomes remarkable and the amount of abrasion of the opposite increases at the same time. Due to this, it is confirmed that when the amount of the hard particles is in the range of 0.1 to 15 10 mass%, high tensile strength and high elongation are exhibited while the

Abrasion resistance is improved, resulting in obtaining an abrasion-resistant sintered aluminum alloy having higher tensile strength than the abrasion-resistant sintered aluminum alloy of Sample A33, which is a conventional aluminum-silicon alloy. It is also found that the effect of improving the abrasion resistance is particularly large when the amount of the hard particles is in the range of 1.0 to 10 mass%.

Comparing sample A06 with samples A09-A12, the effect of zinc on the amount added is examined. From the results, it is understood that the amount of the intermetallic compound precipitated in the aluminum alloy matrix in the sample A09 having 2.0 mass% of zinc is so small that the tensile strength is small though the elongation is large. In addition, their coating pressure is low although the hard particles are added at 5.0 mass%. With a zinc content of 3.0 mass%, although the elongation is reduced by increasing the amount of the intermetallic zinc compound precipitated in the aluminum alloy matrix, the tensile strength and the lay-up pressure 30 are increased by the effect of this increased amount of the intermetallic compound and the Increases the effect of the increased density of the sintered mass, which is caused by the increased amount of Zn liquid phase and / or eutectic phase of Zn and another element. When the amount of the precipitated zinc intermetallic compound is excessive, the strength is rather lowered, so that the tensile strength and the coating pressure at the peaks on the sample appear to be 35A06 at 5.5 mass% Zn and then decrease at the sample A11, containing 10 mass% Zn. In addition, in the sample A12 in which the Zn content exceeds 10 mass%, it was found that the sintered compact was melted to produce an excessive amount of the zinciferous liquid phase during sintering, thus canceling the subsequent forging step, the heat treatment and tests 40 leads. Due to this, it can be confirmed that the zinc content of 3.0 to 10 mass% is effective for improving the tensile strength and the coating pressure.

Comparing the sample A06 with the samples A13 to A17, the effect of magnesium on the addition amount is examined. From the results, it is understood that the amount of intermetallic compound 45 precipitated in the aluminum alloy matrix in the sample A13 having 0.1 mass% Mg is so small that the tensile strength is small although the elongation is large. In addition, the coating pressure is low although hard particles of 5.0 mass% are added. At a magnesium content of 0.5 mass% or more, although the elongation is reduced by increasing the amount of the intermetallic compound precipitated in the aluminum alloy matrix, the tensile strength and the covering pressure are increased by the effect of this increased amount of the intermetallic compound and increases the effect of the increased density of the sintered mass caused by the increased amount of the Mg liquid phase and / or eutectic phase of Mg and another element. When the amount of the precipitated intermetallic compound is excessive, the strength is quite deteriorated, so that the tensile strength and the coating pressure at the peaks 22 AT 500 508 B1 on the sample A06 appear to be 2.5 mass% Mg and then to Reduce sample A16 with 5 mass% Mg. Moreover, in the sample A17 in which the Mg content exceeds 5.0 mass%, it was found that the sinter compact was deformed with the excessive amount of the zinciferous liquid phase generated during sintering, resulting in deletion of the subsequent forging step passing heat treatment and trials. Due to this, it can be confirmed that the magnesium content of 0.5 to 5.0 mass% is effective in improving the tensile strength and the coating pressure.

Comparing sample A06 with samples A18-A22, the effect of copper on the amount of addition is examined. From the results, it is understood that the amount of the intermetallic compound precipitated in the aluminum alloy matrix in the sample A18 of 0.1 mass% Cu is so small that the tensile strength is small although the elongation is large. In addition, the coating pressure is low although the hard particles of 5.0 mass% are added. At a copper content of 0.5 mass% or more, although the elongation is reduced by increasing the amount of the intermetallic compound precipitated in the aluminum alloy matrix, the tensile strength and the covering pressure are increased by the effect of this increased amount of the intermetallic compound and increases the effect of the increased density of the sintered mass caused by the increased amount of Cu liquid phase and / or eutectic phase of Cu and other elements. When the amount of the precipitated intermetallic compound is excessive, the strength is rather damaged, so that the tensile strength and the coating pressure appear to be 1.5 mass% Cu on peaks on the sample A06 and then 5 on the sample A21 , 0 mass% of copper decrease. Moreover, in the sample A22 in which the Cu content exceeds 5.0 mass%, the sinter compact was deformed with the excessive amount of the zinciferous liquid phase generated during sintering, resulting in the deletion of the subsequent forging step, the Heat treatment and the experiments led. Due to this, it can be confirmed that the copper content of 0.5 to 5.0 mass% is effective in improving the tensile strength and the coating pressure. Comparing sample A06 with samples A23 and A24 in Table 1-3, the effect of the hard particles on their nature is examined. From the results, it is understood that sufficient abrasion resistance (coating pressure) may be achieved even if the kind of the hard particles is changed from boron carbide to silicon carbide or chromium boride. It has been found that particularly when chromium boride is used, it is possible to provide an excellent abrasion resistant sintered aluminum alloy which not only has higher tensile strength than the abrasion resistant sintered aluminum alloy (Sample A33) of the conventional aluminum-silicon type but also has a same occupancy pressure. Comparing sample A06 with samples A25-A29 in Tables 1-3, the effect of the low melting metal powder on the addition amount is examined. From the results, it is understood that sufficient tensile strength, elongation and coating pressure are obtained even when the low-melting metal powder is not added, and in particular, the tensile strength and elongation are higher than those of the abrasion-resistant sintered aluminum alloy (Sample A33) of conventional aluminum-silicon type. In addition, it should also be understood that these properties are improved by adding 0.01 to 0.5 mass% of a low-melting metal powder to the abrasion-resistant sintered aluminum alloy of this invention. When this addition exceeds 0.5 mass%, the low-melting metal in the grain boundary of the aluminum alloy matrix precipitates and the above properties deteriorate. Due to this, it can be confirmed that although no addition of the low-melting metal powder is allowed, its addition of 0.01 to 0.5 mass% is effective for improving the tensile strength, elongation and coating pressure. Comparing the sample A06 with the samples A30-A32 in Tables 1 to 3, the effect of the low-melting metal powder of the kind thereof was studied. From the results, it is understood that even if the kind of the low-melting metal powder is changed from tin to bismuth, indium or eutectic compounds thereof (lead-free solder), the same improvement effect as tin in terms of tensile strength, elongation and stress is obtained can. (Example 2)

In this example, using the raw material powder prepared in Example 1 and the same mixing ratio for Sample A03, 5.5 mass% zinc powder; 2.5% by mass of magnesium powder, 1.5% by mass of copper powder; 5 mass% boron carbide powder; 0.1 mass% tin powder; and remainder aluminum powder sintered aluminum alloy specimens prepared by carrying out the same operation of Example 1 except that the compacting pressure, sintering conditions (temperature increasing rate in the range of 400 ° C to sintering temperature, sintering temperature and time) and forging conditions (heating temperatures of the sintered compact and forging die Anstauchverhältnis) as shown in Table 4 were changed. With regard to all these samples, the same evaluation as in Example 1 was carried out. The results are shown in Table 5. 20

Table 4 25 30 35 40 45 50

Sample No. Compacting Sintering Forging Pressure MPa Rise Rate ° C / min Sinter Temp. ° C Sintering time min Temp. ° C Anchoring ratio% A34 100 10 600 20 400 40 A35 200 10 600 20 400 40 A06 300 10 600 20 400 40 A36 400 10 600 20 400 40 A37 300 10 600 20 400 40 A38 300 5 600 20 400 40 A06 300 10 600 20 400 40 A39 300 15 600 20 400 40 A40 300 20 600 20 400 40 A41 300 10 580 20 400 40 A42 300 10 590 20 400 40 A06 300 10 600 20 400 40 A43 300 10 610 20 400 40 A44 300 10 620 20 400 40 A45 300 10 600 0 400 40 A46 300 10 600 10 400 40 A06 300 10 600 20 400 40 A47 300 10 600 30 400 40 A48 300 10 600 40 400 40 A49 300 10 600 20 - - A50 300 10 600 20 Rt. 3 A51 300 10 600 20 Rt. 10 55 2 4 AT 500 508 B1

Table 4 (continued)

Sample No. Compacting Sintering Forging Pressure MPa Rise Rate ° C / min Sinter Temp. ° C Sintering time min Temp. ° C Anvelling ratio% A52 300 10 600 20 Rt. 20 A53 300 10 600 20 Rt. 40 A54 300 10 600 20 Rt. 45 A53 300 10 600 20 Rt. 40 A55 300 10 600 20 100 40 A56 300 10 600 20 150 40 A57 300 10 600 20 200 40 A58 300 10 600 20 300 40 A06 300 10 600 20 400 40 A59 300 10 600 20 450 40 A60 300 10 600 20 500 40 A61 300 10 600 20 400 3 A62 300 10 600 20 400 10 A63 300 10 600 20 400 20 A06 300 10 600 20 400 40 A64 300 10 600 20 400 70 A65 300 10 600 20 400 80 A66 200 10 550 60 - - A33 200 10 550 60 450 40 35 40 45 50 55 o GJ o

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Ol Red Ol CD O Ol O Table 5 Sample Density Ratio% Evaluation Comments No. Green Compact Sintered Compact Forged Compact Tensile strength. MPa Elongation% Coating pressure MPa A34 90.5 - - - - - Deformation of the sintered mass A35 92.4 96.5 99.3 520 3.5 40 A06 92.5 96.5 99.3 520 3.5 40 A36 94 , 2 97.8 99.3 520 3.1 40 A3 7 - - - - - - Nozzle wear A38 92.5 95.0 98.8 473 1.8 30 A06 92.5 96.5 99.3 520 3, 5 40 A3 9 92.5 96.2 99.2 510 3.3 40 A40 92.5 96.8 99.3 523 3.4 40 A41 92.5 88.0 99.3 410 2.6 25 A4 2 92.5 96.2 99.3 482 3 35 A06 92.5 96.5 99.3 50 3.5 40 A43 92.5 96.8 99.3 515 3.1 40 A4 4 92.5 - -. - - - Melting of the sintered mass A4 5 92.5 95.5 99.3 410 2.4 25 A4 6 92.5 96.1 99.3 512 3.4 40 A06 92.5 96.5 99.3 520 3 , 5 40 A4 7 92.5 96.3 99.3 515 3.3 40 AT 500 508 B1 cn cn cn ο • U cn o co o ro o cn

NJ CD

Table 5 (continued) Sample No. Density Ratio% Interpretation Comments Green compact Sintered compact Forged compact Tensile strength MPa Elongation% Loading MPa A4 8 92.5 96.8 99.3 521 3.2 40 A4 9 92.5 96.5 - 450 1,1 20 A50 92,5 96,5 99,3 480 1,2 35 1 A51 92,5 96,5 99,3 483 1,2 40 A52 92,5 96,5 99,4 488 1, 4 40 A53 92.5 96.5 99.3 495 1.3 40 A54 92.5 96.5 - - - - Tear A53 92.5 96.5 99.3 495 1.3 40 A55 92.5 96, 5 99.3 505 2.6 40 A56 92.5 96.5 99.3 510 3 40 A57 92.5 96.5 99.3 522 3.2 40 A58 92.5 96.5 99.3 520 3, 4 40 A06 92.5 96.5 99.3 520 3.5 40 A59 92.5 96.5 99.3 523 3.6 40 A60 92.5 96.5 99.3 - - - Adhesion to the A61 stamp 92 , 5 96.5 99.3 485 2.8 40 A62 92.5 96.5 99.3 492 3 40 A63 92.5 96.5 99.3 518. 3.2 40 AT 500 508 B1

NJ "" I

Table 5 (continued) Sample No. Density Ratio% Evaluation Comments Green compact Sintered compact Forged compact Tensile strength MPa Elongation% Loading MPa A06 92.5 96.5 99.3 520 3.5 40 A64 92.5 96.5 99, 3 511 3.3 40 A65 92.5 96.5 - - - - Tear A66 85.0 87.0 - 300 1.3 20 Alloy according to JP-A-H7-224341 A3 3 85.0 87.0 99, 8 360 2.5 50 alloy according to JP-A-H7-224341 AT 500 508 B1 28 AT 500 508 B1

Comparing Sample A06 to Nos. A34-A37 in Tables 4 and 5, the effect of compaction pressure is examined. From the results, it is understood that a compact pressure in a range of 200 to 400 MPa gives a green compact sample having a high density ratio, resulting in a sintered aluminum alloy having high tensile strength and high elongation by the sintered forge heat treatment method. In contrast, the green compact of the sample A34 in which the compacting pressure is less than 200 MPa has a low density, and the sintered mass thereof thus causes deformation by a large shrinkage due to the generation of the liquid phase, resulting in the painting of the subsequent forging step, the heat treatment and the experiments led. On the other hand, in the green compact of Sample A37, where the compacting pressure exceeds 400 MPa, the adhesion (nozzle wear) of the sinter compact at the nozzle occurred when the compact was taken out of the nozzle, as well as painting the subsequent forging step. the heat treatment and the experiments led. Due to this, it is confirmed that the compacting is necessarily performed at a compacting pressure 15 of 200 to 400 MPa.

Comparing Sample A06 with Nos. A38-A40 in Tables 4 and 5, the effect of the temperature elevation rate in the range of 400 ° C to the sintering temperature is examined. From the results, it is understood that in the sample A38 in which the temperature increase rate is less than 10 ° C / min, the Zn component volatilizes from the compact during sintering and the amount of the precipitation phase decreases leads to deterioration of tensile strength, elongation and distillation pressure. On the other hand, in the samples in which the temperature elevation rate is 10 ° C or more, it is observed that they each exhibit a high degree of tensile strength, elongation and coating pressure. On the basis of this, it is confirmed that the temperature elevation rate in the range of 400 ° C to the sintering temperature is necessarily 10 ° C / min.

Comparing Sample A06 with Nos. A41-A44 in Tables 4 and 5, the effect of the sintering temperature is examined. From the results, it is understood that in the samples in which the sintering temperature is within the range of 590 to 610 ° C, the sample exhibits high levels of tensile strength, elongation and coating pressure. In contrast, in Sample A41 where the sintering temperature is lower than 590 ° C, both the tensile strength and the elongation are lowered. The reason for this is considered that the constituent element added in the form of a simple metal powder is not fully dissolved in the Al base and forms a solid solution remaining locally segregated, with the result that the respective sample has a small value of mechanical property. In contrast, in Sample A44 where the sintering temperature is more than 610 ° C, the melting of the sinter compact due to the excessively generated liquid phase occurs. The subsequent test for the evaluation was therefore deleted. Due to this, it is confirmed that the sintering temperature is not necessarily in the range of 590 to 610 ° C.

Comparing Sample A06 with No. A45-A48 in Tables 4 and 5, the effect of the sintering time is examined. From the results, it is understood that in the sample A45 where the sintering time is less than 10 minutes, low values of strength, elongation 45 and coating pressure are obtained. The reason is presumably that when the sintering time is short, the component is not sufficiently dissolved in the Al base and forms a solid solution remaining locally segregated, with the result that the respective sample has a small mechanical value Has properties. On the other hand, in the samples in which the sintering time is 10 minutes or more, the component is uniformly dissolved in the So base to form a solid solution. Therefore, the respective samples exhibit high values of tensile strength, elongation and coating pressure. Even if the sintering time exceeds 30 minutes, these properties are not changed much. Therefore, setting the sintering time to 30 minutes or less is sufficient. When comparing the samples A49-A66 in Tables 4 and 5, the effect whether the 29 AT 500 508 B1

Forging is performed or not and the effects of the forging temperature and the Anstauchverhältnis examined.

By comparing the sample A49, which is the abrasion-resistant sintered aluminum alloy in the present invention, with the sample A66, which is a water-resistant, sintered aluminum alloy of the conventional aluminum-silicon type in which each forging is not performed, have the Elongation and the coating pressure in each case the same value for both samples. In view of the tensile strength, it is confirmed that Sample A49 of this invention is excellent and exhibits a higher value than the conventional sample. 10

When compared with sample A49 where forging is not carried out, samples A50-65 (except those where the evaluation test was omitted for inadequacy) at which forging was conducted are reported in terms of tensile strength, elongation, and the occupancy pressure improved. Therefore, the effect of performing the forging step was confirmed.

The forging conditions are examined below. When comparing Samples A49-A54, it is found that when the swaging ratio is in the range of 3 to 40% in cold forging, the effect of improving tensile strength, elongation, and coating pressure can be seen. Conversely, if the swaging ratio exceeds 40% as in the specimen of No. A54, cracks in the specimen due to forging occur. The evaluation test of the sample was therefore canceled.

Comparing sample A35 (cold forging) with Nos. A06 and A55-A60, it is also understood that in hot forging with changes in sintering composition and forging die temperatures, the tensile strength may be improved while the elongation is significantly improved. This is attributable to the fact that, although in cold forging hairline cracks easily remain within the sample, with subsequent reduction of elongation, performing the hot forging of the material at the set heating temperature of 30-100 ° C or more, the hairline cracks are removed. On the other hand, if the forging temperature exceeds 450eC, adhesion (nozzle wear) of the sintered compact occurs at the nozzle. Therefore, the test was canceled in such a case.

When comparing the sample A06 and the samples A61-A65, it is understood that even if the staking ratio is applied within a wide range of 3 to 70%, the effect of the improvement in the tensile strength, elongation and coating pressure can be seen. On the other hand, if the upset ratio exceeds 70% as in the A65 sample, the forging causes cracks in the sample. Therefore, the test was canceled in such a case. 40

As described above, it is confirmed that the tensile strength, elongation and coating pressure improving effect are obtained by adding, after the sintering step, either the cold forging step in which the sinter compact is forged at room temperature and an upset ratio of 3 to 40%, or the hot forging step at 45, the sinter compact is forged at a temperature of 100 to 450 ° C and an upsetting ratio of 3 to 70%. (Example 3) Thus, in this example, a comparison was made between the case where zinc is incorporated in the form of aluminum alloy powder (B01) and the case where it is in the form of a simple zinc powder (B02). Specifically, in the starting material powder mixing step for B01, aluminum powder having a particle size of 100 mesh became minus sieve; Aluminum alloy powder with 12 mass% Zn; Boron carbide powder having a particle size of 55 125 mesh minus sieve as powder for the hard particles; Zinc powder, magnesium powder, copper

L 30 AT 500 508 B1 powder and tin powder, each having a particle size of 250 mesh minus sieve, prepared to prepare a starting material powder having a total composition of Zn: 5.5%, Mg: 2.5%, Cu: 1, 5%, Sn: 0.1%, hard particles (boron carbide): 5.0% and balance Al and unavoidable impurities by mixing and mixing these powders together according to the mixing ratio shown in Table 5.

In the compacting step, by setting the compacting pressure to 300 MPa, the raw material powder was formed into columnar compacts having dimensions of Φ40 mm × 28 mm. In the sintering step, the compact was heated in a nitrogen gas atmosphere by raising the heating temperature within a range of 400 ° C to the sintering temperature of 600 ° C at a temperature elevation rate of 10 ° C / min, and was sintered by standing at the sintering temperature of 20 ° C Minutes was held. Thereafter, the compact was cooled from the sintering temperature to 450 ° C at a cooling rate of -20 ° C / min. In the forging step, the sintered compact thus obtained was heated at 400 ° C and placed in a nozzle 15 at the same temperature to carry out the hot forging at an upsetting ratio of 40%. In the heat treatment step, forged compact was heated at 470 ° C to conduct the solution treatment, and was then held at 130 ° C for 24 hours to perform the aging precipitation treatment. For evaluation of the respective samples B01 and B02 obtained, five columnar pieces of φ40 mm x 28 mm were processed into a tensile test piece, and the tensile test was conducted to measure the tensile strength and elongation. The result is shown as an average value and as a value 3 σ in Table 7. In addition, two other columnar pieces are each cut into a wear test piece having a pillar shape of φ7.98 mm × 20 mm, 25, and slid on them on a pin-on-table abrasion resistance test machine at a sliding speed of 5 m / sec for 30 minutes using an inverse of S45C heat treated material under constant load and machine oil feed. If a drastic change in the dynamic friction coefficient during the slip test was observed, the test piece was replaced with another and the load was increased by 5 MPa each time. The load at which a drastic increase in the dynamic friction coefficient was observed was determined as the covering pressure (critical bearing pressure). The results are shown in Table 7. In the preparation of each sample, the density ratio for the green compact after the compacting step, the sintered compact after the sintering step, and the forged compact after the forging step 35 were measured. The results are shown in Table 7. It is noted that the conditions for the compaction to aging precipitation treatment for the sample B02 are the same as for the sample A06. 40 45 50 55 • ί. Ο ro ο οι

CO

Table 6 Sample No. Mixing ratio Composition% Al powder Al alloy powder Zn powder Mg powder Cu powder Hard particle powder Low melting metal powder Al Zn Type Art BOI 45 Balance Balance 12.0 2.5 1.5 b4c powder 5 , 0 Sn powder 0.1 B02 balance 5.5 2.5 1.5 B4C powder 5.0 Sn powder 0.1

Table 7 Sample No. Density Ratio% Evaluation Green compact Sintered compact Smeared compact Tensile strength MPa Elongation% Coverage MPa Average 3 σ Average 3 σ B01 85.0 93.0 99.0: 525 18 4.0 1.0 40 B02 87 , 0 93.0 99.0 520 28 · 3.5 1.2 40 AT 500 508 B1 32 AT 500 508 B1

From the results of Tables 6 and 7, it is confirmed that the tensile strength becomes slightly higher and the fluctuation in tensile strength can be suppressed particularly to a small value range when Zn in the form of the alloy powder is added with Al (Sample B01) in comparison to the case when Zn is added in the form of a simple component powder (Sample B02). In addition, the elongation is also improved and the fluctuation is suppressed to a small range. This is considered to be an effect of preventing the volatilization of zinc by adding the zinc component, which is easily volatilized, to the alloy form, and thus the zinc content in the sample does not fluctuate. In contrast, an equivalent value for the coating pressure is obtained. In this example, it is confirmed that the improvement and suppression of the fluctuation of tensile strength and elongation can be achieved without a reduction in the coating pressure by adding zinc to the alloy mold becomes. (Example 4) 15

In the raw material powder mixing step, aluminum powders having a particle size of 100 mesh are minus sieve; Aluminum alloy powder of the composition according to Table 8; Magnesium powder, copper powder and tin powder as low-melting metal powders each having a particle size of 250 mesh minus sieve; and boron carbide powder having a particle size of 125 mesh minus sieve as a powder for the hard particles, to prepare a raw material powder by mixing and mixing these powders together according to the mixing ratio shown in Table 8. Using these raw material powders, the compacting step, sintering step, forging step and heat treatment step were carried out under the same conditions as in Example 3 to prepare a sample having the composition shown in Table 9.

In the preparation of the sample, the green compact density ratio after the compacting step, the sintered compact after the sintering step and the forged compact after the forging step were measured, and the measurement of tensile strength, elongation and stress (critical wear pressure) was also performed, and the results are shown in Table 10. 35 40 45 50 55 ω

Table 8 ω

Sample Mixing ratio Mass% No Al powder Al alloy powder Mg powder Cu powder Hard particle powder Low melting metal powder Al Zn Type Type B03 0.0 Remainder Balance 12.0 2.5 1.5 B4C powder 5.0 Sn Powder 0.1 B04 1.0 remainder remainder 12.0 2.5 1.5 B4C powder 5.0 Sn powder 0.1 B05 15.0 balance remainder 12.0 2.5 1.5 B4C powder 5.0 Sn powder 0.1 BO 6 25.0 balance remainder 12.0 2.5 1.5 B4 <: powder 5.0 Sn powder 0.1 BOI 45.0 remainder balance 12.0 2, 5 1.5 B4C powder 5.0 Sn powder 0.1 B07 65.0 remainder balance 12.0 2.5 1.5 B4C powder 5.0 Sn powder 0.1 B08 75.0 remainder balance 12 , 0 2.5 1.5 B4C powder 5.0 Sn powder 0.1 B09 17.5 balance remainder 7.5 2.5 1.5 B4C powder 5.0 Sn powder 0.1 BIO 35, 8 remainder remainder 10.0 2.5 1.5 B4 <: - powder 5.0 Sn powder 0.1 BOI 45.0 balance remainder 12.0 2.5 1.5 B4C powder 5.0 Sn powder 0.1 Bll 54.2 remainder remainder 15.0 2.5 1.5 B4C powder 5.0 Sn powder 0.1 B12 63.3 balance remainder 20.0 2.5 1.5 B4C powder 5, 0 Sn powder 0.1 B13 72.5 remainder balance 30.0 2.5 i, 5 B4C powder 5.0 Sn powder 0.1 B14 77.1 remainder Balance 40.0 2.5 1.5 B4C powder 5.0 Sn powder 0.1 B15 60.9 balance remainder 10.0 2.5 1.5 B4C powder 5.0 Sn powder 0.1 B16 57.5 remainder remainder 30.0 2.5 1.5 B4C powder 5.0 Sn powder 0.1 &gt; ui ο

Ul ο 00 00

α &gt;

Alzn Mg Cu Hard Particles Other Type Type BO 3 Balance 10.9 2.5 1.5 b4c 5.0 Sn 0.1 B04 Balance 10.8 2.5 1.5 b4c 5 , 0 Sn 0.1 BO 5 residue 9.1 2.5 1.5 b4c 5.0 Sn 0.1 B06 residue 7.9 2.5 1.5 b4c 5.0 Sn 0.1 BOI residue 5.5 2.5 1.5 b4c 5.0 Sn 0.1 BO 7 balance 3.1 2.5 1.5 b4c 5.0 Sn 0.1 B08 balance 1.9 2.5 1.5 b4c 5.0 Sn 0.1 B09 residue 5.5 2.5 1.5 b4c 5.0 Sn 0.1 BIO residue 5.5 2.5 1.5 b4c 5.0 Sn 0.1 BOI residue 5.5 2.5 1 , 5 b4c 5.0 Sn 0.1 Bll residue 5.5 2.5 1.5 b4c 5.0 Sn 0.1 B12 residue 5.5 2.5 1.5 b4c 5.0 Sn 0.1 B1 3 Balance 5.5 2.5 1.5 b4c 5.0 Sn 0.1 B14 balance 5.5 2.5 1.5 b4c 5.0 Sn 0.1 B15 balance 3.0 2.5 1.5 b4c 5 , 0 Sn 0.1 B16 remainder 10.0 2.5 1.5 b4c 5.0 Sn 0.1 AT 500 508 B1 CO Table 10 m sample NR. Density ratio% Evaluation Remarks Green compact Sealed compact Smear compacted Tensile strength MPa Elongation% Coating pressure MPa B03 72.0 - - - - - severe deformation during sintering B04 76.0 - - - - - severe deformation during sintering B05 80, 0 92.0 99.0 510 2.0 40 B06 83.0 92.0 99.0 514 2.6 40 BOI 85.0 93.0 99.0 525 4.0 40 B07 87.0 93.0 99 , 0 501 4.0 40 B08 90.0, 93.0 99.3 475 4.0 30 B09 74.0 88.0 99.0 510 0.7 35 BIO 80.0 91.0 99.0 520 2 , 0 40 BOI 85.0 93.0 99.0 525 4.0 40 Bll 56.0 93.0 99.0 515 3.5 40 B12 88.0 93.0 99.0 507 3.0 40 B13 90 , 0 92.0 99.0 500 2.0 40 B14 92.0 90.0 99.0 240 0.9 30 B15 87.0 91.0 99.0 515 3.8 40 B16 86.0 90.0 99.0 507 1.0 40 AT 500 508 B1 36 AT 500 508 B1

Comparing the samples B01 and B03-B08 in Tables 8 to 10, the effect of the amount of the added aluminum powder is examined. In the samples B03 and B04 where the amount of the added aluminum powder is less than 15 mass%, as a result of the fact that the amount of Zn in the whole composition of the starting material 5 is excessively large when it is 10 mass% exceeds, the sintered compact due to the liquid phase, which occurs from the interior of the aluminum alloy powder, greatly deformed. The subsequent steps were therefore deleted. On the other hand, when the amount of the added aluminum powder is more than 15 mass%, it becomes possible to sinter without occurrence of deformation of the sintered mass, and the sample exhibits a high degree of tensile strength, elongation and coating pressure. From these results, it is confirmed that when Zn is added as a whole in the form of the aluminum alloy powder, it is necessary to uniformly use the aluminum powder of 15 mass% or more. When the amount of the added aluminum powder exceeds 15 mass%, the respective sample also tends to have increased values of tensile strength and elongation as the amount of the aluminum powder increases. On the contrary, when the amount of Zn in the total composition of the raw material powder exceeds 5.5 mass% (Sample B01), the tensile strength tends to be lowered. In the sample B08 in which the amount of Zn in the whole composition of the raw material powder is lower than 3 mass%, with the result that the amount of zinc is small, the reduction of the tensile strength 20 and the coating pressure in each sample is observed.

Comparing the samples B01 and B09 to B14 in Tables 8 to 10, the effect of Zn content in the aluminum alloy powder is examined. In these comparisons, the amount of Zn in the total composition of the raw material powder in each sample 25 was set to a fixed value. From the results of these samples, it is found that in the sample B09 in which the content of Zn in the aluminum alloy powder is less than 10 mass%, the product exhibits a high value of tensile strength, while the elongation value thereof is small or 0.7% , On the other hand, when the content of Zn in the aluminum alloy powder is 10 mass% or more, it is found that not only the respective sample has a high tensile strength, but the value of elongation is also increased. When the content of Zn in the aluminum alloy powder exceeds 30% by mass, both the reduction in tensile strength and the reduction in elongation are observed (Sample B14). In the coating pressure, a preferable value is obtained when the content of Zn in the aluminum alloy powder is in the range of 10 to 30 mass%, 35 but the reduction in the coating pressure is observed when the content of Zn in the aluminum alloy powder exceeds 30 mass%. Accordingly, it is confirmed that, when the amount of Zn in the aluminum alloy powder is in the range of 10 to 30 mass%, the respective sample exhibits high values of tensile strength, elongation and coating pressure. 40

In the optimum range of Zn content in the aluminum alloy powder confirmed above, the lower limit of Zn in the total composition of the raw material powder and the upper limit thereof can be examined by Sample B15 and Sample B16. As a result, it is confirmed that, when the amount of Zn in the region 45 is from 3 to 10 mass% in the total composition of the raw material powder, the respective samples exhibit high tensile strength, high elongation under high coating pressure with the above-described effect. (Example 5) 50

Example 5 is an embodiment in which the verification of the amounts of Mg and Cu added and the forms of the Mg and Cu added were carried out. In this example, the aluminum powder, aluminum alloy powder, magnesium powder, copper powder, tin powder and boron carbide powder used in Example 3, which were mixed together, were the aluminum alloy powders each having the composition shown in Table 37 AT 500 508 B1 , and having a particle size of 100 mesh minus sieve and the aluminum-magnesium alloy powder in which the Mg content was 50 mass%, the balance being Al and unavoidable impurities, and the particle size was 250 mesh minus sieve. The mixing ratio is shown in Table 11, and the raw material powders having the total composition shown in Table 12 were prepared. Using these raw material powders, the compacting step, sintering step, forging step, heat treatment step and test piece processing step were carried out under the same conditions as in Example 3. For the samples B-17 to B-32 obtained above, the density ratios at each step were measured as well as the mechanical properties, namely the tensile strength, elongation and coating pressure, and the results are shown in Table 13 together with the measurement result (average value). Sample B01 in Example 3 is shown. CO Table 11 oo Sample Mixing ratio Mass% No Al powder Al alloy powder Mg powder Al 50Mg powder Cu powder Powder of hard particles Powder of low-melting metal Al Zn. Cu type Art B17 47.5 remainder balance 12.0 0.0 1.5 B4C powder 5.0 Sn powder 0.1 B18 4.0 balance remainder 12.0 0.5 1.5 B4C powder 5, 0 Sn powder 0.1 B19 46.5 residue balance 12.0 1.0 1.5 B4C powder 5.0 Sn powder 0.1 BOI 45.0 balance residue 12.0 2.5 1.5 B4C Powder 5.0 Sn powder 0.1 B20 42.5 remainder balance 12.0 5.0 1.5 B4C powder 5.0 Sn powder 0.1 B21 42.5 remainder balance 12.0 5.0 1.5 B4C powder 5.0 Sn powder 0.1 B22 39.5 balance remainder 12.0 8.0 1.5 B4C powder 5.0 Sn powder 0.1 B23 46.5 remainder remainder 12, 0 2.5 0.0 B4C powder 5.0 Sn powder 0.1 B2 4 46.0 remainder balance 12.0 2.5 0.5 B4C powder 5.0 Sn powder 0.1 BOI 45, 0 remainder remainder 12.0 2.5 1.5 B4C powder 5.0 Sn powder 0.1 B25 44.0 balance remainder 12.0 2.5 2.5 B4C powder 5.0 Sn powder 0, 1 B26 41.5 remainder remainder 12.0 2.5 5.0 B4C powder 5.0 Sn powder 0.1 B27 38.5 remainder balance 12.0 2.5 8.0 B4C powder 5.0 Sn Powder 0.1 B28 61.0 remainder balance 12.0 2.0 2.5 V B4C powder 5.0 Sn powder 0.1 B29 61.0 'remainder balance 12.0 5.0 2.5 B4C Powder 5.0 Sn powder 0.1 B30 61.0 remainder rest 12, 0 8.0 2.5 B4C powder 5.0 Sn powder 0.1 B31 61.0 remainder balance 12.0 10.0 2.5 B4C powder 5.0 Sn powder 0.1 B32 61.0 Balance Balance 12.0 15.0 2.5 B4C powder 5.0 Sn powder 0.1 AT 500 508 00

ω CD

Alzn Mg Cu Hard particles Other species Type B17 Residue 5.5 oo 1.5 b4c Ul o Sn 0.1 B18 Balance 5.5 0.5 1.5 b4c 5.0 Sn 0 , 1 B19 remainder 5.5 1.0 1.5. b4c 5.0 Sn 0.1 BOI balance 5.5 2.5 1.5 b4c 5.0 Sn 0.1 B20 balance 5.5 2.5 1.5 b4c 5.0 Sn 0.1 B21 balance 5, 5 5.0 1.5 b4c 5.0 Sn 0.1 B22 Balance 5.5 8.0 1.5 b4c 5.0 Sn 0.1 B23 Balance 5.5 2.5 0.0 b4c 5.0 Sn 0.1 B24 residue 5.5 2.5 0.5 b4c 5.0 Sn 0.1 BOI residue 5.5 2.5 1.5 b4c 5.0 Sn 0.1 B25 residue 5.5 2.5 2 , 5 b4c 5.0 Sn 0.1 B26 residue 5.5 2.5 5.0 'b4c O in Sn 0.1 B27 residue 5.5 2.5 00 o b4c 5.0 Sn 0.1 B28 residue 3 , 8 2.5 0.6 b4c 5.0 Sn 0.1 B29 balance 3.8 2.5 1.6 b4c 5.0 Sn 0.1 B30 balance 3.8 2.5 2.5 b4c 5.0 Sn 0.1 B31 remainder 3.8 2.5 3.1 b4c 5.0 Sn 0.1 B32 remainder 3.8 2.5 4.7 b4c 5.0 Sn 0.1 AT 500 508 B1 ο

Table 13 Sample NR. Density ratio% Evaluation Comments Green compact Sealed compact Smoked compact Tensile strength MPa Expansion% Loading MPa B17 86.0 88.0 99.0 380 1.0 25 B18 85.0 90.0 99.0 490 1, 8 35 B19 85.0 90.0 99.0 510 3.0 40 BOI 85.0 93.0 99.0 525 4.0 40 B20 85.0 93.0 99.0 520 3.8 40 B21 85, 0 82.0 99.0 505 1.6 40 B22 84.0 - - - - - Sintered material deforms strongly B23 85.0 91.0 99.0 400 3.8 25 B24 85.0 92.0 99.0 495 3.8 30 BOI 85.0 93.0 99.0 525 4.0 40 B25 84.0 93.0 99.0 510 2.0 40 B26 81.0 93.0 99.0 501 1.2 35 B27 83.0 - - - - - sintered mass deforms strongly B28 84.0 91.0 99.0 518 2.1 40 B29 85.0 93.0 99.0 531 3.0 40 B30 85.0 93.0 99, 0 520 3.2 40 B31 84.0 91.0 99.0 505 1.8 35 B32 84.0 88.0 99.0 450 0.7 35

AT 500 508 B 41 AT 500 508 B1

Comparing samples B01, B117-B19, B21 and B22 in Tables 11 to 13, the effect of the amount of Mg powder added in the form of a simple metal powder is examined. From the results, it is found that if Mg is not added (Sample B17), if the liquid phase, which would otherwise form Mg, does not occur, the tensile strength, elongation and coating pressure are lowered. In contrast, when Mg is added in the form of a simple metal powder, the tensile strength, elongation and coating pressure are increased when the amount of Mg is 0.5 mass% or more. In the sample B22 in which the amount of Mg exceeds 5 mass%, the amount of the liquid phase occurring becomes excessively large, with the result that the sinter compact deforms. On the basis of these points, it is confirmed that, in view of the amount of Mg in the whole composition of the raw material powder, the effect of increasing the tensile strength, elongation and coating pressure occurs when the amount of Mg is in the range of 0.5 to 5 mass%. Sample B20 is an example in which Mg in the form of the aluminum-magnesium alloy powder is added. In comparison with the sample B01, it is found that when the amount of Mg is equal to the total composition of the starting powder, equivalent values of tensile strength, elongation and coating pressure are obtained even when Mg in the form of the aluminum-magnesium alloy powder is added becomes. 20

By comparing the samples B01 and B23-B27 in Tables 11 to 13, the effect of the amount of Cu powder added in the form of a simple metal powder is examined. From the results, it is found that when Cu is not added (Sample B23), in which the liquid phase that would otherwise precipitate Cu does not occur, both the tensile strength and the coating pressure are low. In contrast, when Cu is added in the form of a simple metal powder, the tensile strength and the lay-up pressure are increased when the Cu amount is 0.5 mass% or more. When the sample B27 in which the amount of Cu exceeds 5 mass%, the amount of the exiting liquid phase becomes excessively large, with the result that the sintered compact is deformed. On the other hand, the elongation tends to decrease as the amount of Cu increases, but may be maintained at 1.0% or more when the amount of Cu is in the range of up to 5 mass%. On the basis of this, it is confirmed that in view of the amount of Cu in the whole composition of the raw material powder, the effect of increasing the tensile strength and the moving pressure when the amount of Cu is in the range of from 0.5 to 5 mass%, and the amount Cu in this range is preferred because a sufficient level of elongation is available.

By comparing samples B28-B32 in Tables 11 to 13, the effect of the amount of Cu is examined when Cu is added in the form of an aluminum alloy powder containing Zn 40 therein. In this case, when Cu is added in the form of a simple metal powder, the reinforcement of the tensile strength and the coating pressure is observed in comparison with the product, if Cu is not added at all (sample B23). In view of the amount of Cu in the overall composition of the raw material powder, it is found that even if it falls within the range of 0.5 to 5 mass%, the above 45 is confirmed if the amount of Cu in the aluminum alloy powder exceeds 10 mass% , the tensile strength and elongation are reduced. From this result, it is further confirmed that when Cu is added in the form in which it is alloyed in the aluminum alloy powder containing Zn therein, the upper limit of Cu in the alloy must be 10 mass%. 50 (Example 6)

Example 6 is an embodiment in which the test was performed on the amount of the hard particles and the kind thereof. Together with the aluminum powder, aluminum alloy powder, magnesium powder, copper powder, tin powder and boron carbide powder of 42 AT 500 508 B1

Example 3, the lithium carbide powder and chromium chloride powder, each having a particle size of 125 mesh minus sieve were used. These powders were blended together with the blending amount shown in Table 14 to prepare starting material powders each having a total composition shown in Table 15. Using these starting material powders, the compatting step, sintering step, forging step, heat treatment step and test piece processing step were carried out under the same conditions as in Example 3, to obtain the products of samples B33-B42. In the obtained samples, measurement of density ratios at each step as well as tensile strength, elongation and coating pressure were conducted, and the results are shown in Table 16 together with the measurement result (average value) of Sample B01 of Example 3.

As the conventional material, aluminum powder and aluminum-silicon alloy powder having 20 mass% Si and balance Al each having a particle size of 100 mesh minus sieve; Nickel powder, copper-nickel alloy powder comprising 4 mass% Ni and balance 15 Cu, and aluminum-magnesium alloy powder comprising 50 mass% Mg and balance aluminum each having a particle size of 250 mesh minus sieve, to obtain In the compacting step, the compacting pressure was set to 200 MPa, and in the sintering step, the compact was set in a nitrogen gas atmosphere by raising the heating temperature within a range of 400 ° C heated to the sintering temperature of 550 ° C at a temperature elevation rate of 10 ° C / min, and the sintering temperature was 60 minutes before cooling from the sintering temperature to 450 ° C at a cooling rate of -20 ° C / min. In the forging step, the heating temperature of the sintered compact and the die was 450 ° C, and the staking ratio 25 was 40%. In the heat treatment step, the temperature for the solution treatment was 470 ° C, and the aging precipitation was carried out at 130 ° C for 24 hours to produce an alloy disclosed in JP-A-H07-224341. For this sample (B43), the measurement of the density ratio after each step as well as the mechanical properties, namely, the tensile strength, elongation and the coating pressure were carried out. These results are shown in Table 16. 35 40 45 50 55 (Jl Ο CJ1 o

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Table 14 Sample No. Mixing ratio Composition% Al powder Al alloy powder Mg powder Cu powder Hard particle powder Low melting metal powder Al Zn Type Art. B33 45.0 Remainder Balance 12.0 2.5 1.5 B4C powder 0, 0 Sn powder 0.1 B34 45.0 balance remainder 12.0 2.5 1.5 B4C powder 0.1 Sn powder 0.1 B35 45.0 balance remainder 12.0 2.5 1.5 B4C Powder 0.5 Sn powder 0.1 B36 45.0 remainder balance 12.0 2.5 1.5 B4C powder 1.0 Sn powder 0.1 B37 45.0 remainder balance 12.0 2.5 1.5 B4C powder 2.5 Sn powder 0.1 BOI 45.0 balance remainder 12.0 2.5 1.5 B4C powder 5.0 Sn powder 0.1 B38 45.0 remainder remainder 12, 0 2.5 1.5 B4C powder 7.5 Sn powder 0.1 B39 45.0 balance remainder 12.0 2.5 1.5 B4C powder 10.0 Sn powder 0.1 B40 45.0 Balance Balance 12.0 2.5 1.5 B4C Powder 12.5 Sn Powder 0.1 BOI 45.0 Balance Balance 12.0 2.5 1.5 B4C Powder 5.0 Sn Powder 0.1 B41 45.0 balance remainder 12.0 2.5 1.5 SiC powder 5.0 Sn powder 0.1 B42 45.0 balance remainder 12.0 2.5 1.5 CrB2 ~ powder 5.0 Sn Powder 0.1 B43 Al-20 Si powder: 75%, Cu-4Ni powder: 4.2%, Al-50Mg powder: 1% , Al powder: remainder AT 500 508 00

Al Zn Mg Cu Hard Particles Low Melting Metal Powder Art Type B33 Balance 6.1 2.5 1.5 B4C 5.0 Sn 0.1 B34 Balance 6.1 2.5 1.5 b4c 5 , 0 Sn 0.1 B35 radical 6.0 2.5 1.5 b4c 5.0 Sn 0.1 B36 radical 6.0 2.5 1.5 b4c 5.0 Sn 0.1 B37 radical 5.8 2 , 5 1.5 b4c 5.0 Sn 0.1 BOI residue 5.5 2.5 1.5 b4c 5.0 Sn 0.1 B38 residue 5.2 2.5 1.5 b4c 5.0 Sn 0, 1 B39 radical 4.9 2.5 1.5 b4c 5.0 Sn 0.1 B40 radical 4.6 2.6 1.5 b4c 5.0 Sn 0.1 BOI radical 5.5 2.5 1.5 b4c 5.0 Sn 0.1 B41 balance 5.5 2.5 1.5 sic 5.0 Sn 0.1 B42 balance 5.5 2.5 1.5 CrB2 5.0 Sn 0.1 B43 Al - 15 % Si - 4% Cu - 0.17% Ni - 0.5% Mg AT 500 508 B1

Table 16 Sample NR. Density ratio% Evaluation Comments Green compact Sealed compact Smoked compact Tensile strength MPa Elongation% Loading pressure MPa B33 88.0 93.0 99.0 560 11.0 20 B34 86.0 93.0 99.0 550 8, 6 30 B35 86.0 93.0 99.0 545 7.1 35 B36 86.0 93.0 99.0 540 6.0 40 B37 85.0 93.0 99.0 530 5.4 40 BOI 85, 0 93.0 99.0 525 4.0 40 B38 85.0 93.0 99.0 508 3.1 40 B39 84.0 92.0 99.0 501 1.6 35 B40 82.0 91.0 99 , 0 485 0.8 30 high abrasion on the contrary BOI 85.0 93.0 99.0 525 4.0 40 B41 85.0 93.0 99.0 535 5.6 45 B42 85.0 93.0 99, 0 548 7,0 50 B43 85,0 87,0 99,0 360 2,5 50 'σι AT 500 508 46 AT 500 508 B1

Comparing the samples B01 and B33-B40 of Tables 15 to 16, the effect of the amount of hard particles is examined. From the results, it is understood that the sample B33 containing no hard particles exhibits high tensile strength and elongation, but the coating pressure is small, which means that the material has a low abrasion resistance. Even in such a material, the abrasion resistance by the hard particles can be improved in an amount of 0.1 mass% or more, so that the coating pressure is increased while suppressing the drop of the tensile strength to a small extent. In particular, the addition of 1.0 mass% or more provides a high abrasion resistance. On the other hand, the elongation tends to decrease slightly as the amount of the hard particles increases, but it is still possible to obtain a sufficient elongation of 1% or more with an amount of 10 mass% or less of the hard particles. When the amount of the hard particles exceeds 10 mass% (Sample B40), the reduction in elongation becomes remarkable and falls below 1%, and at the same time, it has been observed that the abrasion amount of the contrary is increased. Due to this, it is confirmed that when the amount of the hard particles is in the range of 0.1 to 10 mass%, high tensile strength and high elongation are exhibited while the abrasion resistance is improved, resulting in higher abrasion resistant sintered aluminum alloy Tensile strength than the abrasion resistant sintered aluminum alloy of sample B43, which is a conventional aluminum-silicon alloy. It is also found that the effect of improving the abrasion resistance is particularly large when the amount of the hard particles is in the range of 1.0 to 10 mass%.

Comparing the samples B01, B41 and B42 in Tables 14 to 16, the effect of the kind of the hard particles is examined. From the results, it is understood that a sufficient abrasion resistance (coating pressure) is obtained even when the kind of the hard particles is changed from boron carbide to silicon carbide or chromium boride. It has also been found that, in particular, when chromium boride is used, it is possible to obtain an excellent abrasion resistant sintered aluminum alloy which not only exhibits higher tensile strength than the conventional aluminum-silicon type abrasion resistant sintered aluminum alloy (Sample B43) , but also an equivalent value of the occupancy pressure. (Example 7) 35 Example 7 is an embodiment wherein the inspection of the amounts of the sintering aid powder and the kind thereof was carried out. Together with the aluminum powder, aluminum alloy powder, magnesium powder, copper powder, boron carbide powder and tin powder of Example 3, the bismuth powder, indium powder and lead-free solder powder each having a particle size of 200 mesh minus sieve were used, and the lead-free soldering powder had a composition of Zn was 8 mass% and the amount of Bi was 3 mass%, with the remainder being Sn and unavoidable impurities. These powders were mixed together in the proportion for mixing in Table 17 to prepare starting material powders having the total composition shown in Table 17. Using these starting material powders, the compacting step, sintering step, forging step, heat treatment step 45 and test piece processing step and the same conditions as in Example 3, to obtain the products of samples B44 to B51. The obtained samples were measured for density at each step as well as tensile strength, elongation and coating pressure, and the results are shown in Table 19 together with the measurement result (average value) of Sample B01 of Example 3. 50 55

Table 17 Sample No. Mixing ratio Composition% Al powder Al alloy powder Mg powder Cu powder Hard particle powder Low-melting metal powder Al Zn Kind Species B44 45.0 Balance Remainder 12.0 2.5 1.5 B4C powder 5, 0 - - B45 45.0 balance remainder 12.0 2.5 1.5 B4C powder 5.0 Sn powder 0.01 B46 45.0 remainder remainder 12.0 2.5 1.5 B4C powder 5, 0 Sn powder 0.05 BOI 45.0 Balance Balance 12.0 2.5 1.5 B4C powder 5.0 Sn powder 0.1 B47 45.0 Balance Balance 12.0 2.5 1.5 B4C Powder 5.0 Sn powder 0.5 B48 45.0 remainder balance 12.0 2.5 1.5 B4C powder 5.0 Sn powder 0.7 BOI 45.0 remainder balance 12.0 2.5 1.5 B4C powder 5.0 Sn powder 0.1 B49 45.0 balance remainder 12.0 2.5 1.5 B4C powder 5.0 bi-powder 0.1 B50 45.0 remainder remainder 12, 0 2.5 1.5 B4C powder 5.0 In powder 0.1 B51 45.0 balance remainder 12.0 2.5 1.5 B4C powder 5.0 Sn-8Zn-4Bi powder 0.1 -vj AT 500 508

GO 00

TABLE 18 Sample No. Total Compositions Compositions Al Zn Mg Cu Hard Particles Low Melting Metal Powder Art Type B44 Balance 5.5 2.5 1.5 b4c 5.0 - - B45 Balance 5.5 2.5 1.5 b4c 5.0 Sn 0.0 B46 residue 5.5 2.5 1.5 b4c 5.0 Sn 0.1 BOI residue 5.5 2.5 1.5 b4c 5.0 Sn 0.1 B47 residue 5.5 2.5 1.5 b4c 5.0 Sn 0.5 B48 balance 5.4 2.5 1.5 b4c 5.0 Sn 0.7 BOI balance 5.5 2.5 1.5 b4c 5.0 Sn 0.1 B4 9 residue 5.5 2.5 1.5 b4c 5.0 Bi 0.1 B50 residue 5.5 2.5 1.5 b4c 5.0 In 0.1 B51 residue 5.5 2.5 1.5 b4c 5.0 Sn Bi 0.09 0.003 AT 500 508 B1

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Table 19 Sample NR. Density ratio% Evaluation Comments Green compact Sealed compact Smoked compact Tensile strength MPa Elongation% Loading pressure MPa B44 85.0 90.0 99.0 501 3.1 35 B45 85.0 93.0 99.0 520 3, 6 40 B46 85.0 93.0 99.0 525 4.0 40 BOI 85.0 93.0 99.0 525 4.0 40 B47 85.0 93.0 99.0 515 3.1 40 B48 85, 0 93.0 99.0 495 2.3 30 BOI 85.0 93.0 99.0 525 4.0 40 B49 85.0 93.0 99.0 528 4.2 40 B50 85.0 93.0 99 , 0 520 3,8 40 B51 85,0 93,0 99,0 528 4,0 40

&lt; D AT 500 508 B1 50 AT 500 508 B1

Comparing the samples B01 and B44-48 of Tables 17 to 19, the effect of the amount of the low-melting metal powder was examined. Compared with the product (Sample B44) in which no low melting point metal is added, it is found that when the low melting point metal is added, the tensile strength, elongation and movement pressure are improved. It is also found that the effect of it is observed in the addition amount when it is in the range of 0.01 to 0.5 mass%; and the effect is highest when the addition amount is in the range of 0.05 to 0.1 mass%. When the addition amount thereof exceeds 0.5 mass%, the reduction in elongation is remarkable accompanied with a reduction in the coating pressure. Accordingly, it is confirmed that the addition of the low-melting metal powder causes the effect of improving the mechanical properties, if any Addition is in the range of 0.01 to 0.5 mass%.

Comparing the samples B01 and B49-B51 shown in Tables 17 to 19, wherein the kind of the low-melting metal powder is changed, the effect of the kind of the low-melting metal powder is examined. From these results, it is confirmed that the same effect as described above is obtained even when the bismuth powder, indium powder or lead-free solder powder is used instead of tin powder. 20 (Example 8)

Example 8 is an embodiment in which the inspection is performed when the compacting pressure is changed as a compacting condition or when the sintering temperature and the sintering time are changed as the sintering condition. 25

Using the raw material powder prepared by using aluminum powder, aluminum alloy powder, magnesium powder, copper powder and tin powder and adjusting the same constituent composition as Example 3, the compacting step and sintering step were performed using the compacting pressure, the sintering temperature and the sintering time shown in Table 20 performed. Under the same conditions as in Example 3, the forging step, heat treatment step and test piece processing step were carried out. With respect to each product obtained, the measurement of the density ratio at each step and the tensile strength, elongation and coating pressure were made. The results are shown in Table 21 together with the result (average value) 35 of Sample B01 in Example 3. 40 45 50 55 5 25 30 35 40 45 50 51 AT 500 508 B1 10 15 20 Table 20 Sample Compacting Sintering No. Pressure Sintering time Sintering time MPa ° C min B52 100 600 20 B53 200 600 20 B01 300 600 20 B54 400 600 20 B55 500 600 20 B56 300 550 20 B67 300 580 20 B01 300 600 20 B58 300 610 20 B59 300 620 20 B60 300-0 B61 300 600 10 B01 300 600 20 B62 300 600 30 B63 300 600 40 55

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Table 21 Sample HR. Density ratio% Evaluation Comments Green compact Sealed compact Smoked compact Tensile strength MPa Elongation% Loading pressure MPa B52 75.0 - - - - - severe deformation during sintering B53 83.0 90.0 99.0 527 3.8 40 BOI 85.0 93.0 99.0 525 4.0 40 B54 85.0 93.0 99.0 530 4.2 40 B55 86.0 - - - - - Nozzle wear B56 85.0 86.0 99.0 415 1.0 20 B57 85.0 92.0 99.0 520 2.6 35 BOI 85.0 93.0 99.0 525 4.0 40 B58 85.0 93.0 99.0 525 3.2 40 B59 85.0 - - - Melting of the sintered mass B60 85.0 91.0 99.0 418 1.2 20 B61 85.0 92.0 99.0 520 3.2 40 BOI 85.0 93.0 99.0 525 4.0 40 B62 85.0 93.0 99.0 526 3.8 40 B63 85.0 94.0 99.0 525 3.6 40 AT 500 508 B1 53 AT 500 508 B1

From the results of samples B01 and B52-B55 in Tables 20 and 21, it is found that when the compacting pressure is in the range of 200 to 400 MPa, a compacted compact sample has a density ratio of 80% or more and that Passing through the sintering-forging heat treatment step, the product of each sample exhibits a high degree of tensile strength and high values of elongation and coating pressure. In the sample B52 where the compacting pressure is below 200 MPa, the amount of shrinkage due to the occurrence of the liquid phase is large because the density of the green compact is low. This caused the loss of form. As a result, the subsequent forging and heat treatment steps were canceled and the respective test was also stopped. On the other hand, when the compacting pressure exceeds 400 MPa (in the sample B55), nozzle wear occurs, whereby the subsequent sintering step and the steps thereafter are canceled and the test is interrupted.

Comparing samples B01 and B56-B59 of Tables 20 and 21, the effect of the sintering temperature is examined. From these results, it is found that the samples B01, B67 and B58, in which the sintering temperature is in the range of 580 to 610 ° C, exhibit a high degree of tensile strength and a high elongation value. On Sample B56, where the sintering temperature is lower than 580 ° C, on the other hand, both the tensile strength and the elongation are deteriorated. Presumably, the constituent element is not completely dissolved in the Al base to form a solid solution and remains locally segregated, with the result that the mechanical properties deteriorate to a low level. In contrast, in the sample B59 in which the sintering temperature is higher than 610 ° C, the sintered compact is deformed upon melting because the amount of the liquid phase excessively occurs. The subsequent test was therefore canceled.

Comparing Samples B01 and B60-B63 of Tables 20 and 21, the effect of the sintering time is examined. From the results, it is found that in the sample B60 in which the sintering time is shorter than 10 minutes, the tensile strength and elongation are deteriorated. It is considered that the constituent element is not sufficiently dissolved in the Al base to form the solid solution and remains locally segregated, with the result that the mechanical properties take a low value. In contrast, in the samples B01 and B61-B63 in which the length of the sintering time is longer than 10 minutes, the component is uniformly dissolved in the Al base to form a solid solution, whereby the relevant product has a high degree of mechanical property while the tensile strength is 500 MPa or more, and the elongation exceeds 3%. Here it should be noted that when the sintering time exceeds 30 minutes, the mechanical property exhibited by the product has no change. Therefore, a sintering time of 30 minutes or less may be considered sufficient. (Example 9)

In Example 9, the procedure of Example 3 was repeated under the same conditions for the sample production as in Example 3 except that the forging conditions were changed as shown in Table 22 to prepare the product samples B-53 to B-69 Use of the aluminum powder, aluminum alloy powder, magnesium powder, copper powder and tin powder used for the sample B01 in Example 3 and preparing the raw material powders adjusted to the same constituent composition as in Example 3. For each of these samples, the density ratio after each step was measured as well as the tensile strength, elongation and coating pressure, and the results are shown in Table 22 together with the measurement results on Sample B01 in Example 3. In Table 22, at the column "forging temperature &quot; the term &quot; Rt. (Room temperature) &quot; In the case of cold forging and hot forging, the heating temperature for a sintered compact sample is shown as a material for forging. The sample B64 is prepared for comparison with a sample of a conventional material similar to the material of Japanese Laid-Open Patent Publication JP-A-H04-365832 in which no forging was performed.

Table 22 10 15 20 25 30

Sample Forging No. Forging Temperature Aspiration Ratio ° C% B64 - - B65 Rt. 3 B66 Rt. 10 B67 Rt. 20 B68 Rt. 40 B69 Rt. 45 B68 Rt. 40 B70 100 40 B71 150 40 B72 200 40 B73 300 40 B01 400 40 B74 450 40 B75 500 40 B76 400 3 B77 400 10 B78 400 20 B01 400 40 B79 400 70 B80 400 80 35 40 45 50 55 CO o ro o cn cn ο cn o Table 23 Sample NR. Density ratio% Evaluation Remarks Green compact Sealed compact Smoked compact Tensile strength MPa Elongation% Loading pressure MPa B64 85.0 93.0 99.0 405 0.5 15 B65 85.0 93.0 99.0 475 0.6 20 B66 85.0 93.0 99.0 480 0.8 25 B67 85.0 93.0 99.0 480 0.8 25 B68 85.0 93.0 99.0 485 1.1 30 B69 85.0 93.0 - - - - Slips occur on B68 85.0 93.0 99.0 485 1.1 30 B70 85.0 93.0 99.0 510 1.9 35 B71 85.0 93.0 99.0 515 2.8 40 B72 85.0 93.0 99.0 520 3.4 40 B7 3 85.0 93.0 99.0 525 4.0 40 BOI 85.0 93.0 99.0 525 4.0 40 B74 85.0 93.0 99.0 526 3.2 40 B75 85.0 93.0 - - - - Nozzle adhesion during forging B76 85.0 93.0 99.0 520 1.9 40 B77 85.0 93 , 0 99.0 522 3.3 40 üi Oi AT 500 508

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Table 23 (continued) Sample NR. Density ratio% Evaluation Comments Green compact Sealed compact Smoked compact Tensile strength MPa Elongation% Loading pressure MPa B78 85.0 93.0 99.0 525 3.6 40 BOI 85.0 93.0 99.0 525 4.0 40 B79 85.0 93.0 99.0 524 4.2 40 B80 85.0 93.0 - - - - Uneven forging and tears AT 500 508

DO

Claims (20)

57 AT 500 508 B1 When comparing samples B64-B69 in Tables 22 and 23, the effect of the upset ratio caused when cold forging at room temperature is examined. From these results, it is found that in the case of cold forging, the sample has high values of tensile strength, elongation, and coating pressure when the tipping ratio is set in a range of 3 to 40. In contrast, cracks in the sample due to forging occur when the upset ratio exceeds 40% (Sample B69). The conduct of the test in this case has been canceled. The effect of the heating temperature when the hot forging is carried out is examined by comparing the samples B68 (cold forging), B01 and B70-B75 in Tables 22 and 23, wherein the heating temperature for the sintered compact is changed. From these results, it is found that the values of tensile strength, elongation and coating pressure are improved by transition to hot forging. This is attributable to the fact that although in cold forging, hairline cracks remain slightly within the sample, with subsequent reduction in elongation, performing hot forging with the material having the heating temperature set at 100 ° C or more removes the hairline cracks , On the other hand, if the forging temperature exceeds 400 ° C, adhesion (nozzle wear) of the sinter compact occurs at the nozzle. The subsequent test in such a case was therefore deleted. Comparing Samples 65 through 69 in Table 18, the effect of the upset ratio is examined in the case where hot forging occurs. From these results, it is found that in hot forging, the samples have high values of tensile strength and coating pressure and a high value of elongation even if the staking ratio 25 is extended to a wide range of 3 to 70%. If the upset ratio exceeds 70% (Sample B80), forging causes the occurrence of cracks in the samples. The subsequent test was therefore canceled in such a case. It is to be understood that this invention is in no way limited to the above embodiments 30 and that many changes can be made without departing from the scope of the invention as defined by the appended claims. Claims 1. An abrasion resistant, high strength sintered aluminum alloy comprising, by mass: 3.0 to 10% zinc; 0.5 to 5.0% magnesium; 0.5 to 5.0% copper; 0.1 to 10% hard particles; an unavoidable amount of impurities, and aluminum and having a metallographic structure comprising: an aluminum alloy matrix dispersed in hard particles; and an intermetallic compound phase precipitated in the aluminum alloy matrix. An abrasion resistant sintered aluminum alloy according to claim 1, wherein said hard particles have an average particle size of 1 to 100 μm. 45 An abrasion-resistant sintered aluminum alloy according to claim 1, wherein the hard particles are composed of a material having a Vickers hardness of 600 Hv or more and have substantially no reactivity with aluminum. so The abrasion resistant sintered aluminum alloy according to claim 1, wherein the hard particles are composed of at least one material selected from the group consisting of silicon carbide, chromium boride and boron carbide and the intermetallic compound phase comprises at least one selected from the group consisting of MgZn 2, Al 2 Mg 3 Zn 3 and CuAl 2 , 55 58 AT 500 508 B1 The abrasion resistant sintered aluminum alloy according to claim 1, further comprising at least one reagent selected from the group consisting of tin, bismuth, indium, and both a eutectic compound and a monotactic compound, each containing at least one element of tin, bismuth and indium as a main component, wherein the content of the reagent in the abrasion-resistant sintered aluminum alloy is 0.01 to 0.5 mass%. A process for producing a high-strength, abrasion-resistant sintered aluminum alloy, comprising: preparing a raw material powder comprising, based on the mass, 3.0 to 10% zinc, 0.5 to 5.0% magnesium, 0.5 to 5.0% of copper, 0.1 to 10% of hard particles, unavoidable amount of impurities, and balance of aluminum by using an aluminum powder having a particle size of 140 μm or less, a hard particle powder having a particle size of 113 μm or less and a combination of simple metal powders, combination of binary alloy powders and combination of a simple metal powder and a binary alloy powder comprising zinc, magnesium and copper and having a particle size of 74 μm or less; Pressing the raw material powder in a die at a compacting pressure of 200 MPa or more to form a compact having a predetermined shape; 20 sintering the compact in a non-oxidizing atmosphere, heating the compact of 400 ° C to a sintering temperature of 590 to 610 ° C at a temperature elevation rate of 10 ° C / min or more and maintaining the sintering temperature for 10 minutes or more before cooling the sinter compact to room temperature; and performing a heat treatment with the compact after sintering, comprising: heating the compact at a temperature of 460 to 490 ° C and quenching with water so as to dissolve a precipitation phase in the aluminum base of the compact to produce a solid solution; and maintaining the temperature in a range of 110 to 200 ° C for 3 to 28 hours to produce a precipitation phase of the solid solution. 30 The production method according to claim 6, further comprising before the heat treatment: performing cold forging or hot forging with the sinter compact, wherein the cold forging comprises pressurizing the sinter compact at room temperature with an upsetting ratio in a range of from 3 to 40% and hot forging pressurizing the sintered compact at a temperature of 100 to 450 ° C with an upsetting ratio in a range of 3 to 70%. 8. The manufacturing method according to claim 6, wherein the hard particles are composed of a material having a Vickers hardness of 600 Hv or more and have substantially no reactivity with aluminum. 9. The manufacturing method according to claim 6, wherein the hard particles are composed of at least one material selected from the group consisting of silicon carbide, chromium boride and boron carbide. 10. The manufacturing method according to claim 6, further comprising before pressurizing: adding at least one reagent to the raw material powder selected from the group consisting of tin, bismuth, indium, and both a eutectic compound and a monotactic compound, each at least one of tin, bismuth and indium as a main component, wherein the content of the reagent is 0.01 to 0.5 mass% as the total amount of the reagent and the raw material powder. The production method according to claim 6, wherein the non-oxidizing atmosphere in the sintering is a nitrogen gas atmosphere having a dew point of -40 ° C or lower. A process for producing a high-strength, wear-resistant sintered aluminum alloy, comprising: producing a raw material powder comprising, by mass, 3.0 to 10% zinc, 0.5 to 5.0% magnesium, 0.5 to 5.0% copper, 0.1 to 10% hard particles, unavoidable amount of impurities, and balance aluminum by using: a simple aluminum powder containing at least 15% by weight of the starting material powder, an aluminum alloy powder containing all the zinc, which is the starting material; io contains material powder; and a powder for the hard particles containing 0.1 to 10 mass% of the raw material powder; Pressing the raw material powder in a die at a compacting pressure of 200 MPa or more to form a compact having a predetermined shape; Sintering the compact in a non-oxidizing atmosphere at a sintering temperature 15 of 580 to 610 ° C for 10 minutes or more before cooling the sinter compact to room temperature; and carrying out a heat treatment with the compact after sintering, comprising: heating the compact at a temperature of 460 to 490 ° C and quenching with water so as to dissolve a precipitation phase in the aluminum base of the compact to produce a solid solution; and maintaining the temperature in a range of 110 to 200 ° C for 2 to 28 hours to produce a precipitation phase of the solid solution. The production method according to claim 12, further comprising before the heat treatment: performing cold forging or hot forging with the sinter compact, wherein the cold forging comprises pressurizing the sinter compact at room temperature with an upsetting ratio in a range of from 3 to 40% and hot forging pressurizing the sintered compact at a temperature of 100 to 450 ° C with a Anstauchverhältnis in the range of 3 to 70%. 14. The manufacturing method according to claim 12, wherein the aluminum alloy powder has a composition comprising 10 to 30% by mass of zinc, an unavoidable amount of impurities and the balance of aluminum. 15. The production method according to claim 12, wherein in the production, the aluminum alloy powder contains 10% by mass or less of copper. A production method according to claim 12, wherein the hard particles are composed of a material having a Vickers hardness of 1000 Hv or more and have substantially no reactivity with aluminum. 40 17. The manufacturing method according to claim 12, wherein the hard particles are composed of at least one material selected from the group consisting of silicon carbide, chromium boride and boron carbide. The manufacturing method according to claim 12, further comprising before pressurizing: adding at least one reagent to the raw material powder selected from the group consisting of tin, bismuth, indium, and both a eutectic compound and a monotactic compound each comprising at least one element of tin, bismuth and indium as a main component, wherein the content of the reagent is 0.01 to 0.5 mass% as the total amount of the reagent and the raw material powder. 19. A production method according to claim 12, wherein in the production, the aluminum powder and the aluminum alloy powder have a particle size of 140 μτη or less, a powder 55 for the hard particles have a particle size of 113 μτη or less, and 60 AT 500 508 B1 continue to produce the use of at least one powder having a particle size of 74 μτη or less for magnesium and copper. The production method according to claim 12, wherein the non-oxidizing atmosphere in the sintering is a nitrogen gas atmosphere having a dew point of -40 ° C or less. No drawing 10 15 20 25 30 35 40 45 50 55