JP2017095808A - Manufacturing method of liquid phase sintered aluminum alloy member and liquid phase sintered aluminum alloy member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a liquid phase sintered aluminum alloy member capable of effectively providing the liquid phase sintered aluminum alloy member having high strength and excellent in dimensional accuracy and the liquid phase sintered aluminum alloy member with high density.SOLUTION: There is provided a manufacturing method of a liquid phase sintered aluminum alloy member having a molding process for molding a raw material powder containing an aluminum alloy powder containing at least one kind of element selected from Si, Mg, Cu and Zn and the balance Al with inevitable impurities, a sintering process for conducting liquid phase sintering on the molded body to obtain a sintered body, a softening process for heating the sintered body and then conducting water hardening to obtain a softened material and a correction process for conducting sizing on the softened material to obtain a corrected material and an aging process for conducting a heat treatment on the corrected material to obtain an aged material with a deposition deposited.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a liquid phase sintered aluminum alloy member suitable for various machine parts and the like, and a liquid phase sintered aluminum alloy member. In particular, the present invention relates to a method for producing a liquid phase sintered aluminum alloy member that can efficiently obtain a liquid phase sintered aluminum alloy member having high strength and excellent dimensional accuracy.

  Sintered members are used for machine parts in various fields such as automobiles, office automation equipment, and household electrical appliances. Sintered members are excellent in mechanical properties such as strength and wear resistance, and can be manufactured in a shape close to the final product shape, and thus are suitable for materials of products having a complicated three-dimensional shape.

  Along with the reduction in weight of machine parts, sintered members made of lighter materials have been demanded, and materials using aluminum alloys have been proposed. For example, Patent Document 1 discloses a liquid-phase sintered aluminum alloy that aims to achieve both strength and wear resistance by adding hard particles to an aluminum alloy. This liquid phase sintered aluminum alloy is formed by forming a mixed powder obtained by mixing aluminum alloy powder and hard particles into a compact, and subjecting this compact to liquid phase sintering to form a sintered body. Obtained by sizing and heat treatment.

JP 2009-242883 A

  However, in the above technique, the sintered body of the liquid phase sintered aluminum alloy is first sized and then heat treated, and the sintered body is dimensional accuracy and the manufacturing method is productivity. There is room for further improvement.

  The present invention has been made in view of the above circumstances, and one of the objects of the present invention is a liquid phase sintered aluminum which can efficiently obtain a liquid phase sintered aluminum alloy member having high strength and excellent dimensional accuracy. It is providing the manufacturing method of an alloy member. Another object of the present invention is to provide a liquid phase sintered aluminum alloy member having high strength and excellent dimensional accuracy.

The manufacturing method of the liquid phase sintered aluminum alloy member of the present invention includes the following steps.
(A) A molding step of molding a raw material powder containing an aluminum alloy powder containing at least one element selected from Si, Mg, Cu and Zn, the balance being Al and inevitable impurities, to form a compact.
(B) A sintering step in which the compact is subjected to liquid phase sintering to form a sintered body.
(C) The softening process which heat-processes to the said sintered compact and makes it a softening material.
(D) A straightening step of sizing the softening material to obtain a straightening material.
(E) An aging process in which the orthodontic material is heat treated to obtain an aging material in which precipitates are deposited.

  The liquid phase sintered aluminum alloy member of the present invention contains at least one element selected from Si, Mg, Cu and Zn, and the liquid phase sintered aluminum containing an aluminum alloy composed of Al and inevitable impurities as the balance. An alloy member having a relative density of 98% or more and a tensile strength of 200 MPa or more.

  The method for producing a liquid phase sintered aluminum alloy member of the present invention can produce a liquid phase sintered aluminum alloy member having high density and high strength and excellent dimensional accuracy with high productivity.

  The liquid phase sintered aluminum alloy member of the present invention has high density and high strength, and is excellent in dimensional accuracy.

It is a graph which shows the elongation and hardness of the alloy in each process in the manufacturing method of the liquid phase sintering aluminum alloy member which concerns on embodiment. It is a graph which shows the heat processing temperature in a softening process, hardness, and electrical conductivity in the manufacturing method of the liquid phase sintered aluminum alloy member which concerns on embodiment. It is a graph which shows the hardness transition of the alloy after a softening process in the manufacturing method of the liquid phase sintered aluminum alloy member which concerns on embodiment. It is explanatory drawing explaining the measuring method of the squareness of the sample in a test example.

[Description of Embodiment of the Present Invention]
The present inventors paid attention to the liquid-phase sintered body before sizing as a matter that greatly affects the dimensional accuracy when examining the increase in the dimensional accuracy of the sintered body. The liquid phase sintered body is obtained by molding raw material powder to form a molded body, and liquid phase sintering the molded body. In general, a liquid-phase sintered body has a high density and a high strength because the pores between the raw material powders are reduced by the liquid phase, and there are fewer holes than a solid-phase sintered sintered body. On the other hand, this sintered body has a large dimensional shrinkage due to rapid densification during sintering, and a large distortion is often generated, and a dimensional correction with a large correction amount is often required.

  When sizing such a liquid-phase sintered body, if the sizing allowance (the amount of dimensional correction associated with plastic working) is large, the sintered body is likely to be broken, resulting in a decrease in yield. This is because if a large sizing allowance is applied to a high-density, high-strength liquid-phase sintered body, it is difficult for the sintered body to follow the sizing mold. This is because there may occur. For example, in the case of a cylindrical or cylindrical liquid phase sintered body, distortion occurs in a direction perpendicular to the side surface, and the size of the sizing allowance for the distortion is as large as 0.5% or more of the total length of the side surface.

  Therefore, the present inventors further studied to improve the plastic deformability of the sintered body when sizing the liquid phase sintered body. As a result, if the liquid phase sintered body is softened by heat treatment and then sized, cracking of the sintered body can be reduced even when the sizing allowance is large, and a liquid phase sintered member with high dimensional accuracy can be obtained with high yield. Obtaining the knowledge that it can be obtained, the present invention has been completed. The contents of the embodiments of the present invention will be listed and described below.

(1) The manufacturing method of the liquid phase sintering aluminum alloy member of embodiment comprises the following processes.
(A) A molding step of molding a raw material powder containing an aluminum alloy powder containing at least one element selected from Si, Mg, Cu and Zn, the balance being Al and inevitable impurities, to form a compact.
(B) A sintering step in which the compact is subjected to liquid phase sintering to form a sintered body.
(C) The softening process which heat-processes to the said sintered compact and makes it a softening material.
(D) A straightening step of sizing the softening material to obtain a straightening material.
(E) An aging process in which the orthodontic material is heat treated to obtain an aging material in which precipitates are deposited.

  According to the method for producing a liquid phase sintered aluminum alloy member of the above-described embodiment, by performing liquid phase sintering, the voids between the raw material powders are reduced by the liquid phase, and solid phase sintering is performed. Compared to the body, there are fewer holes and the density is high, and a sintered body with high strength can be obtained. By applying heat treatment to the sintered body and then sizing the softened material, the softened material is improved in elongation and soft, so that the generation of cracks during sizing can be suppressed and the yield can be improved. In addition, since the softening material can easily follow the mold during sizing, a liquid phase sintered aluminum alloy member having excellent dimensional accuracy can be efficiently manufactured.

  (2) As a manufacturing method of the liquid phase sintered aluminum alloy member of the embodiment, the softening step may be performed at a temperature at which the elongation of the softening material is 2% or more.

  When the softening material has an elongation of 2% or more, cracks are less likely to occur during sizing. In addition, the softer the softening material, the easier it is to follow the mold, and thus the dimensional accuracy is easily improved.

  (3) As a manufacturing method of the liquid phase sintered aluminum alloy member of embodiment, performing the said softening process at the temperature of 455 degreeC or more and 520 degrees C or less is mentioned.

  By setting the heat treatment temperature in the softening step within the above range, the elongation of the softening material is easily set to 2% or more. When the heat treatment temperature is 455 ° C. or higher, it is easy to form a softening material having plastic workability that hardly causes cracks during sizing. When the heat treatment temperature is 520 ° C. or lower, sufficient elongation can be obtained during sizing without any further heating, and unnecessary heating can be omitted.

  (4) As a manufacturing method of the liquid phase sintering aluminum alloy member of embodiment, the said softening process includes performing a solution treatment.

  By performing the solution treatment, the additive element can be sufficiently dissolved in the aluminum alloy.

  (5) As a manufacturing method of the liquid phase sintering aluminum alloy member of embodiment, it is mentioned that the said correction process performs the hardness HRB of the said softening material 50 or less.

  Even if heat treatment is performed in the softening step to improve the elongation of the softening material, if left in that state, the hardness increases and the elongation decreases due to natural aging. Therefore, when the softening material has a hardness HRB of 50 or less, the softening material is soft, it is easy to suppress the occurrence of cracks, and it is easy to produce a liquid phase sintered aluminum alloy member excellent in dimensional accuracy with a high yield.

  (6) As a manufacturing method of the liquid phase sintering aluminum alloy member of embodiment, it is mentioned that the said aluminum alloy powder is an Al-Si-Mg-Cu type alloy powder.

  A liquid phase sintered body of an Al—Si—Mg—Cu alloy is excellent in wear resistance. However, since the Al—Si—Mg—Cu-based alloy has a small elongation, it tends to crack during sizing or become a member with poor dimensional accuracy. Then, the liquid phase sintered body of an Al-Si-Mg-Cu type-alloy with high dimensional accuracy can be efficiently manufactured by using the manufacturing method of the liquid phase sintered aluminum alloy member of embodiment mentioned above.

  (7) As the liquid phase sintered aluminum alloy member according to the embodiment, one manufactured by the method for producing a liquid phase sintered aluminum alloy member according to any one of the above (1) to (6) is proposed.

  The liquid phase sintered aluminum alloy member of the embodiment has high density and high strength because liquid phase sintering is performed. In addition, the softening material is sized and the dimensional accuracy is excellent. And since the liquid phase sintered aluminum alloy member of embodiment can be easily manufactured with the manufacturing method of the liquid phase sintered aluminum alloy member of embodiment, it is excellent in productivity.

  (8) The liquid phase sintered aluminum alloy member of the embodiment contains at least one element selected from Si, Mg, Cu, and Zn, and the liquid phase contains an aluminum alloy that consists of Al and inevitable impurities. The sintered aluminum alloy member has a relative density of 98% or more and a tensile strength of 200 MPa or more.

  According to the liquid phase sintered aluminum alloy member of the above-described embodiment, the relative density is as high as 98% or higher, and the tensile strength is as high as 200 MPa or higher.

  (9) As a liquid phase sintering aluminum alloy member of embodiment, it is mentioned that surface roughness Rz is 6 or less.

  The surface roughness Rz of 6 or less means that a liquid phase sintered aluminum alloy member was manufactured along the mold during sizing of the sintered body, and is excellent in dimensional accuracy.

  (10) As a liquid phase sintering aluminum alloy member of embodiment, it is mentioned that a squareness is 0.1% or less of full length.

  When the liquid phase sintered aluminum alloy member has a corner portion that connects two surfaces of the outer peripheral surface constituting the member, the perpendicularity is 0.1% or less of the total length, that is, substantially right angle, so that the dimensional accuracy is improved. Excellent.

  (11) As a liquid phase sintering aluminum alloy member of embodiment, it is mentioned that the said aluminum alloy is an Al-Si-Mg-Cu type alloy.

  By being a liquid phase sintered body of an Al—Si—Mg—Cu alloy, it is excellent in wear resistance.

  (12) The liquid phase sintered aluminum alloy member of the embodiment further includes hard particles made of a nonmetallic inorganic material and dispersed in a matrix phase made of the aluminum alloy.

  By dispersing hard particles in a base material made of an aluminum alloy, wear resistance can be improved as compared to the case of the base material alone.

[Details of the embodiment of the present invention]
Details of the embodiment of the present invention will be described below. In addition, this invention is not limited to these illustrations, is shown by the claim, and intends that all the changes within the meaning and range equivalent to the claim are included. For example, the composition of the raw material powder, the temperature and time of the sintering process, the softening process, and the aging process can be appropriately changed for the test examples described later.

<Method for producing liquid phase sintered aluminum alloy member>
The manufacturing method of the liquid phase sintered aluminum alloy member of the embodiment includes the following preparation process, forming process, sintering process, softening process, straightening process, and aging process.

[Preparation process]
Aluminum alloy powder is prepared as a raw material powder. Furthermore, if necessary, a plurality of hard particles can be mixed to form a mixed powder.

(Aluminum alloy powder)
The aluminum alloy powder contains at least one element selected from Si, Mg, Cu and Zn, and the balance is made of an aluminum alloy of Al and inevitable impurities. As the aluminum alloy, Al-Si-Mg-Cu alloy, Al-Zn-Mg-Cu alloy, Al-Si alloy, Al-Cu alloy, Al-Mg alloy, Al-Cu-Si alloy Etc.

  Al-Si-Mg-Cu alloys are preferred because of their excellent wear resistance. As a specific composition of the Al—Si—Mg—Cu-based alloy, Si is 6 mass% or more and 18 mass% or less, Mg is 0.2 mass% or more and 1.0 mass% or less, and Cu is 1.2 mass% or more. Examples include those containing 3.0% by mass or less and the balance being Al and inevitable impurities. In particular, Si is preferably contained in an amount of 8% by mass to 15% by mass.

  An Al—Zn—Mg—Cu alloy is preferable because of its excellent strength. As a specific composition of the Al—Zn—Mg—Cu-based alloy, Zn is 5.1% by mass to 6.5% by mass, Mg is 2.0% by mass to 3.0% by mass, and Cu is 1.% by mass. 2 mass% or more and 2.0 mass% or less, Sn containing 0.1 mass% or more and 0.3 mass% or less, and the remainder consisting of Al and inevitable impurities, and other well-known JIS standard 7075 and 7010 Composition.

  As the raw material powder, an aluminum alloy powder having the same composition as the above-described aluminum alloy may be used, or a high-added aluminum alloy powder having a high concentration of the additive element and a high-purity aluminum powder substantially not containing the additive element. A mixed composite powder may be used. When a soft high-purity aluminum powder is contained, the moldability is excellent. The amount of the high-purity aluminum powder and the concentration of the additive element in the high-added aluminum alloy powder can be appropriately selected. When this composite powder is used, a part of the additive elements of the high-added aluminum alloy powder diffuses into the high-purity aluminum powder in the sintering step described later, and a desired composition is obtained.

  The average particle size of the aluminum alloy powder is preferably about 45 μm to 350 μm. The average particle diameter of the raw material powder can be regarded as substantially the same as the average particle diameter in the aluminum alloy member. An average particle size of 45 μm or more is preferable because it is easy to handle and has excellent handling properties. On the other hand, it is preferably 350 μm or less because it is easy to mold.

  The particle size distribution of the raw aluminum alloy powder is measured by, for example, a microtrack method (laser diffraction / scattering method). The average particle diameter and the maximum diameter of the aluminum alloy particles in the liquid phase sintered aluminum alloy member are measured as follows. An arbitrary cross section of the liquid phase sintered aluminum alloy member is observed with an optical microscope (100 to 400 times), and this observation image is image-processed to measure the area of all aluminum alloy particles present in the cross section. The equivalent circle diameter of each area is calculated, the equivalent circle diameter is defined as the diameter of each particle, and the maximum diameter in the cross section is defined as the maximum diameter of the cross section. The maximum diameter is determined for n = 10 cross sections, and the average of the 10 maximum diameters is defined as the maximum diameter of the aluminum alloy particles. Moreover, the average of the diameters of all the particles in one cross section is taken, the average is obtained for n = 10 cross sections, and the average of the 10 diameters is further averaged to be the average particle diameter of the aluminum alloy particles.

(Hard particles)
The hard particles are non-metallic inorganic materials. Nonmetallic inorganic materials include ceramics, intermetallic compounds, diamond, and the like. In particular, non-metallic inorganic materials of compounds can be suitably used. More specific materials include compounds such as alumina (Al ₂ O ₃ ), mullite (a compound of alumina and silicon oxide), SiC, AlN, and BN in addition to Si alone. Among them, when alumina is used, a member having good reactivity with the metal phase and excellent wear resistance can be obtained, and when mullite is used, a member having low opponent attack can be obtained. These various hard particles may be of a single type, or may be mixed in a plurality of types and contained in a liquid phase sintered aluminum alloy member. The composition of the hard particles in the liquid phase sintered aluminum alloy member (single element, compound element and content) uses, for example, scanning electron microscope-energy dispersive X-ray spectroscopy, X-ray diffraction, chemical analysis, etc. Can be measured.

  The content of hard particles in the liquid phase sintered aluminum alloy member (when multiple kinds of hard particles are contained, the total content) is preferably 0.5% by mass or more and 10% by mass or less. When it is 0.5% by mass or more, it is easy to obtain wear resistance comparable to or higher than that of other sintered members, and furthermore, it can have practically sufficient strength and hardness. A more preferable lower limit is 1% by mass or more. As the hard particle content increases, the wear resistance and hardness improve. However, if it exceeds 10% by mass, the strength is reduced, or when the sliding member is used, for example, the wear or damage of the counterpart material becomes severe, that is, the opponent attack property becomes high. A more preferable upper limit value is 5.0% by mass or less, particularly 3.0% by mass or less.

  The hardness of the liquid phase sintered aluminum alloy member tends to increase as the hardness of the hard particles increases or as the content of the hard particles increases.

  The smaller the average particle size of the hard particles, the better the wear resistance. If the average particle size of the hard particles is too large, the hard particle content increases in order to ensure the same wear resistance as that of the small particles. In the case of alumina particles, the specific particle size is preferably 10 μm or less, more preferably 1 μm or more and 6 μm or less. When the alumina particles having a size satisfying the above range are contained in the specific range, there is an effect of improving the sinterability of the alloy member. In the case of mullite, the average particle size is preferably 20 μm or less, more preferably 1 μm or more and 15 μm or less. Also, if the average particle size of the hard particles is too large, for example, when a sliding member is used, if the hard particles fall off during sliding contact with the counterpart material, the hard particles will slide in an intervening state with the counterpart material. This will worsen the opponent's aggression. Therefore, the maximum diameter of the hard particles is preferably 30 μm or less, more preferably 4 μm or more and 30 μm or less.

  The particle size distribution of the hard particles used as the raw material is measured by, for example, a microtrack method (laser diffraction / scattering method). The average particle diameter and maximum diameter of the hard particles in the liquid phase sintered aluminum alloy member are the same as the method for measuring the average particle diameter and maximum diameter of the aluminum alloy particles.

  The shape of the hard particles preferably has no sharp edge, in other words, is as close to a sphere as possible. For example, the aspect ratio is preferably 1.0 or more and 3.0 or less. By using hard particles close to a sphere or hard particles whose corners are not square, opponent attack can be reduced as compared to the case of using elongated particles.

  The hard particles substantially remain in the aluminum alloy base material. Therefore, the amount and size of the hard particles used as a raw material are adjusted so that the content and size of the hard particles in the alloy have a desired amount and size.

[Molding process]
The prepared raw material powder is filled into a mold and molded. For example, cold pressure forming such as cold mold forming can be used. Examples of the molding pressure include ² ton / cm ² or more and 10 ton / cm ² or less. By adjusting the shape of the cavity of the mold, it is possible to obtain a molded body having a complicated shape.

[Sintering process]
Sintering of the obtained molded body may be performed at the liquid phase appearance temperature, and known conditions can be used. Typical sintering conditions include an inert atmosphere such as nitrogen or argon, temperature: 540 ° C. or more and 620 ° C. or less, time: 0 (start of temperature decrease when reaching specified temperature) or more and 60 minutes or less. Examples of the sintering temperature include 540 ° C. or more and 560 ° C. or less in the case of an Al—Si—Mg—Cu alloy, and 580 ° C. or more and 620 ° C. or less in the case of an Al—Zn—Mg—Cu alloy.

  When a composite powder obtained by mixing high-added aluminum alloy powder and high-purity aluminum powder is used as a raw material powder, a part of the additive elements of the high-added aluminum alloy powder diffuses into the high-purity aluminum powder by this sintering process. . For example, in the case of an Al—Si based alloy, if the raw material powder is a composite powder in which a high Si aluminum alloy powder containing 6 mass% or more of Si and a high purity aluminum powder substantially not containing Si are mixed, This is an aluminum alloy having a two-phase structure having a high Si aluminum alloy phase having a Si content of 6% by mass or more and a low Si aluminum alloy phase having a Si content of 2% by mass or less.

[Softening process]
The obtained sintered body is heat-treated to obtain a softening material with improved elongation. In FIG. 1, 1% by mass of 2 μm alumina powder is mixed with Al—Si—Mg—Cu based alloy powder (average particle size 70 μm) having a composition of Al-14Si-2.5Cu-0.5Mg (unit: mass%). The elongation and hardness when the sintered body formed and liquid phase sintered using the mixed powder is subjected to a softening step and an aging step are shown. In the softening step, water quenching (Water Quench: WQ) was applied at 495 ° C. for 1 hour, and in the aging step, heat treatment (aging treatment) at 175 ° C. for 8 hours was performed. As shown in the graph of FIG. 1, when the sintered body was subjected to a heat treatment (here, equivalent to solution treatment), the elongation (breakage) was about 1.0% as the hardness (Rockwell hardness) decreased. It can be seen that (elongation) is improved to about 3.3%. Thereafter, when an aging treatment is performed, it is understood that the hardness is improved and the elongation is reduced by precipitation strengthening. If sizing in the straightening process described below is applied to the softened material with improved elongation, the softened material can easily follow the mold during sizing, cracking can be suppressed, and members with excellent dimensional accuracy can be produced efficiently. It is considered possible. The elongation (breaking elongation) of the softening material is preferably 2% or more. More preferably, it is 3% or more.

  FIG. 2 shows the heat treatment temperature applied to the sintered body and the hardness HRB and electrical conductivity IACS% of the sintered body (softening material) cooled to room temperature after the heat treatment. The upper graph of FIG. 2 shows 1 mass of 2 μm alumina powder in an Al—Si—Cu—Mg based alloy powder (average particle size 70 μm) having the same composition as Al-14Si-2.5Cu-0.5Mg as in FIG. This is a result of using a sintered body formed by mixing and molding and liquid phase sintering. The lower graph of FIG. 2 shows that 1% by mass of 2 μm alumina powder is mixed with Al—Zn—Cu—Mg alloy powder (average particle size 70 μm) having a composition of Al-5.5Zn-1.5Cu-2.5Mg. This is a result of using a sintered body that was molded and liquid phase sintered. As shown in both graphs of FIG. 2, the hardness (Rockwell hardness) tends to increase as the heat treatment temperature increases, but there is a region where the hardness becomes substantially constant during the temperature increase. In the region where the temperature is constant, the additive element is completely dissolved in the aluminum alloy. Further, when the temperature rises, it becomes a liquid phase, and when it is rapidly cooled, hardness increases. Therefore, the elongation can be improved by performing the heat treatment in a temperature region where the hardness is substantially constant. In the case of an Al—Si—Cu—Mg alloy, such a heat treatment temperature is preferably 480 ° C. or more and 520 ° C. or less, more preferably 480 ° C. or more and 510 ° C. or less, and particularly preferably 486 ° C. or more and 496 ° C. or less. In the case of an Al—Zn—Cu—Mg alloy, the temperature is preferably 460 ° C. or higher and 500 ° C. or lower, more preferably 470 ° C. or higher and 490 ° C. or lower, and particularly preferably 465 ° C. or higher and 495 ° C. or lower. The softened material softened at this heat treatment temperature tends to have an elongation of 2% or more. On the other hand, electrical conductivity tends to decrease as the heat treatment temperature increases, and tends to increase when the heat treatment temperature is too low. This is because when the heat treatment temperature is high, more Cu, Zn or the like is dissolved. If the electrical conductivity is low, Cu, Zn, etc. are in a solid solution, so that the plastic workability is excellent, and the softening material tends to follow the mold during sizing. Therefore, it is preferable to perform the heat treatment in a temperature region where the electrical conductivity is lower. The holding time required for softening requires time for the softening material to become a solid solution sufficiently, and is generally 0.5 hours or more and 2 hours or less, and more preferably 1 hour or more and 1.2 hours or less.

  Also when solution treatment is performed as the heat treatment performed on the sintered body, the heat treatment conditions are the same as the heat treatment conditions (temperature and holding time) described above. After heating, it is preferable to cool at a cooling rate of 100 ° C./s or higher.

[Correction process]
Sizing is applied to a softening material, particularly a softening material having an elongation of 2% or more. FIG. 3 shows the transition of the hardness of the softened material after the softening step of the sintered body (similar to FIG. 2). As shown in the graph of FIG. 3, the hardness (Rockwell hardness) tends to improve with time. As the hardness increases, the elongation decreases. Sizing is preferably performed in a state where the hardness HRB of the softening material is 50 or less. As shown in the graph of FIG. 3, in the case of an Al—Si—Cu—Mg alloy, after 6 hours from the softening step, the hardness HRB is 50 or more and the elongation is less than 2%. In the case of an Al—Zn—Cu—Mg alloy, after 20 hours from the softening step, the hardness HRB is 50 or more and the elongation is less than 2%.

  In order to size the softening material, the softening material is filled into a molding space of a mold having a desired shape and pressed. A general mold can be used. For example, what is provided with the cylindrical die | dye provided with the through-hole, and the upper punch and lower punch which are inserted and arrange | positioned at this through-hole and pressurize and compress a softening material is mentioned. After the softening material is disposed in the molding space formed by the inner peripheral surface of the through hole of the die and the lower punch inserted into one opening of the through hole, the other softening material is disposed in the other opening of the through hole. The softening material is pressed and compressed with a predetermined pressure by the inserted upper punch and the lower punch to form a correction material, and the correction material is extracted from the die. When this mold is used, a columnar correction material corresponding to the contour shape of the die and the end face shapes of the upper punch and the lower punch can be obtained.

  Sizing may be hot or cold. Cold sizing can improve dimensional accuracy, and hot sizing can improve strength. Further, this sizing may be performed either in the case of ironing or in the case of upsetting, but in the case of ironing sizing, a good surface roughness can be obtained.

[Aging process]
An aging material in which precipitates are deposited by heat-treating (aging) the sizing orthodontic material. As for this heat processing temperature, 170 degreeC or more and 210 degrees C or less are mentioned.

<Liquid phase sintered aluminum alloy member>
Since the liquid phase sintered aluminum alloy member produced by the above-described method for producing a liquid phase sintered aluminum alloy member is subjected to liquid phase sintering, the pores between the raw material powders are reduced by the liquid phase, resulting in high density. And high strength. The relative density of this liquid phase sintered aluminum alloy member is 96% or more, preferably 98% or more. Here, the relative density is a value obtained by calculating the actual density of a member made of an aluminum alloy based on the specific gravity of each element and calculating (actual density / true density) × 100. Further, the tensile strength of the liquid phase sintered aluminum alloy member is 200 MPa or more, preferably 250 MPa or more.

  Since the sintered body subjected to liquid phase sintering is subjected to a heat treatment to form a softening material and then sized, the softening material along the mold is easily formed during sizing. Therefore, when having a right angle to the liquid phase sintered aluminum alloy member, the perpendicularity is 0.1% or less of the total length. Moreover, the surface roughness Rz of the liquid phase sintered aluminum alloy member is 6 or less by applying sizing.

  In addition, the liquid phase sintered aluminum alloy member of this embodiment has a small aspect ratio (ratio between the maximum diameter and the minimum diameter) of the base material particles constituting the base material made of the aluminum alloy (less than 5). That is, by examining the alloy structure, it can be confirmed that it was manufactured by sintering.

[Test example]
Liquid phase sintered aluminum alloy members containing various aluminum alloys are prepared. The relative density, tensile strength, squareness, and surface roughness of the obtained liquid phase sintered aluminum alloy member were examined. Moreover, the yield of the liquid phase sintered aluminum alloy member was examined.

(Sample preparation)
・ Sample No. 1: Al-Si-Mg-Cu-based alloy Al-Si-Mg-Cu-based alloy powder having a composition of Al-18Si-3.25Cu-0.81Mg (unit: mass%) Aluminum alloy powder), high-purity aluminum powder having a composition of Al-0.5Mg, and alumina powder are prepared. The average particle diameter of the Al—Si—Mg—Cu alloy powder and the high-purity aluminum powder is 50 μm, and the alumina powder has an average particle diameter of 2 μm (maximum diameter 6 μm). A mixed powder is prepared by mixing the prepared Al—Si—Mg—Cu alloy powder, high-purity aluminum powder, and alumina powder. The mass ratio of the Al—Si—Mg—Cu alloy powder and the high-purity aluminum powder is 80:20, and this ratio is the ratio of the high Si aluminum alloy phase and the low Si aluminum alloy phase in the liquid phase sintered aluminum alloy member. It is a mass ratio. Said each powder is mixed so that alumina powder may be 1.0 mass% with respect to mixed powder. The obtained mixed powder was die-molded at a surface pressure of 5 ton / cm ² to prepare a cylindrical shaped body (diameter: 35 mm × height: 10 mm). Subsequently, this compact was liquid phase sintered in a nitrogen atmosphere under sintering conditions of 550 ± 5 ° C. × 50 minutes.

The obtained sintered body was heated to 495 ° C. for 1 hour, then water-cooled (150 ° C./s) to form a solution, and 0.5 hour later, cold sizing was performed under the condition of 6 ton / cm ² . The hardness (Rockwell hardness) HRB of the softened material 0.5 hours after the solution treatment was 23, and the elongation (breaking elongation) was 2% or more. For the sizing, the above-described cylindrical die and punch were used. Thereafter, aging at 175 ° C. × 8 hours was further performed to prepare a liquid phase sintered Al—Si—Cu—Mg based alloy sample (liquid phase sintered aluminum alloy member).

・ Sample No. 2: Al-Zn-Mg-Cu-based alloy Al-Zn-Mg-Cu-based alloy powder having a composition of Al-6.5Zn-1.75Cu-2.7Mg (unit: mass%) Alumina powder is prepared. The average particle diameter of the Al—Zn—Mg—Cu alloy powder is 70 μm, and the average particle diameter of the alumina powder is 2 μm (maximum diameter 6 μm). A mixed powder is prepared by mixing the prepared Al—Zn—Mg—Cu alloy powder and alumina powder. Said each powder is mixed so that alumina powder may be 1.0 mass% with respect to mixed powder. The obtained mixed powder was mold-molded at a surface pressure of 5 ton / cm ² to produce a molded body. Subsequently, this compact was liquid phase sintered in a nitrogen atmosphere under sintering conditions of 610 ± 5 ° C. × 20 minutes.

The obtained sintered body was heated to 495 ° C. × 1 hour, then water-cooled (150 ° C./s) to form a solution, and after 1 hour, cold sizing was performed on the condition of 6 ton / cm ² . The hardness (Rockwell hardness) HRB of the softened material that passed 1.5 hours after the solution treatment was 23, and the elongation (breaking elongation) was 2% or more. For the sizing, the above-described cylindrical die and punch were used. Thereafter, aging at 175 ° C. × 8 hours was further performed to prepare a liquid phase sintered Al—Zn—Cu—Mg based alloy sample (liquid phase sintered aluminum alloy member).

・ Sample No. 100: Al—Si—Mg—Cu alloy As a comparative product, sample No. Sample No. 1 was prepared by the conventional method (liquid phase sintering → sizing → solution treatment → aging) using the raw material powder of No. 1. 100 is made. This sample has the same processing order after liquid phase sintering as Sample No. except that solution treatment and aging were performed after sizing. 1 was used.

・ Sample No. 200: Al—Zn—Mg—Cu-based alloy Sample No. Sample No. 2 was prepared by the conventional method (liquid phase sintering → sizing → solution formation → aging) using the raw material powder of No. 2. 200 is produced. This sample has the same processing order after liquid phase sintering as Sample No. except that solution treatment and aging were performed after sizing. The conditions were the same as 2.

(Relative density)
The relative density was measured about the liquid phase sintered aluminum alloy member of each produced sample. The relative density is obtained by measuring the actual density using a commercially available density measuring device and calculating the true density of a member made of an aluminum alloy of each composition of the sample based on the specific gravity of each element (actual density / It is calculated by calculating (true density) × 100. The results are shown in Table 1.

(Tensile strength)
About the liquid phase sintered aluminum alloy member of each produced sample, tensile strength was measured with a general-purpose tensile tester based on the metal material tensile test method of JIS Z 2241 (2011). The results are shown in Table 1.

(Surface roughness)
About the liquid phase sintered aluminum alloy member of each produced sample, surface roughness Rz (10-point average roughness) was measured with a commercially available surface roughness measuring instrument based on JIS B 0601 (2001). The results are shown in Table 1.

(right angle)
The liquid phase sintered aluminum alloy member of each prepared sample was measured with a commercially available right angle measuring device (Squara Master, manufactured by Mitutoyo Corporation) based on JIS B 0621 (1984). For example, as shown in FIG. 4, the squareness measurement method applies the dial gauge 11 of the right-angle measuring device 10 to the side surface of the sample 1 and slides the sleeve 12 along the shaft to cover the entire surface of the sample 1 in the height direction. The squareness was measured. The results are shown in Table 1.

(Yield)
The yield was calculated | required about the liquid phase sintered aluminum alloy member of each produced sample. Yield was defined as the ratio of those that were judged as non-defective among the whole (100 manufactured), with those having no cracks or chips in the member as non-defective products and certain products as defective products. The results are shown in Table 1.

  As shown in Table 1, the sample No. manufactured by the manufacturing method of the present embodiment was used. 1 and sample no. 2 has a relative density as high as 98% or more and a tensile strength as high as 317 MPa or more.

  As shown in Table 1, the sample No. 1 was sized after the liquid phase sintered body was solutionized. 1 and sample no. No. 2 has a surface roughness Rz of 6 or less. 100 and sample no. It can be seen that it is smaller than 200. Sample No. 1 and sample no. No. 2 is a sample having a squareness of 0.05% or less. 100 and sample no. It can be seen that it is smaller than 200. These results are considered to be because the softening material was stretched and softened by heat treatment performed before sizing, and the softening material was formed along the shape of the mold during sizing. And when a liquid phase sintering aluminum alloy member is manufactured with the manufacturing method of this embodiment, it turns out that a yield will be 100% and productivity will improve compared with the past.

  The method for producing a liquid phase sintered aluminum alloy member of the present invention can be suitably used for producing a member that is required to have dimensional accuracy with a complicated three-dimensional shape. The liquid phase sintered aluminum alloy member of the present invention can be suitably used as a product material in various fields where high strength and light weight are desired.

1 Sample 10 Right angle measuring instrument 11 Dial gauge 12 Sleeve

Claims (11)

A forming step of forming a raw material powder containing an aluminum alloy powder containing at least one element selected from Si, Mg, Cu and Zn, the balance being Al and unavoidable impurities, and forming a formed body;
A sintering step of subjecting the molded body to liquid phase sintering to form a sintered body;
A softening step of heating the sintered body followed by water quenching to form a softening material;
A straightening step of sizing the softening material to make a straightening material,
A method for producing a liquid phase sintered aluminum alloy member, comprising: an aging step in which a heat treatment is performed on the straightening material to form a aging material in which precipitates are deposited.   The method for producing a liquid phase sintered aluminum alloy member according to claim 1, wherein the softening step is performed at a temperature at which the elongation of the softening material is 2% or more.   The said softening process is a manufacturing method of the liquid phase sintered aluminum alloy member of Claim 2 performed at the temperature of 455 degreeC or more and 520 degrees C or less.   The method of manufacturing a liquid phase sintered aluminum alloy member according to any one of claims 1 to 3, wherein the straightening step is performed with a hardness HRB of the softening material of 50 or less.   The method for producing a liquid phase sintered aluminum alloy member according to any one of claims 1 to 4, wherein the aluminum alloy powder is an Al-Si-Mg-Cu-based alloy powder.   A liquid phase sintered aluminum alloy member produced by the method for producing a liquid phase sintered aluminum alloy member according to claim 1. A liquid phase sintered aluminum alloy member containing an aluminum alloy containing at least one element selected from Si, Mg, Cu and Zn, the balance being Al and inevitable impurities,
Relative density is 98% or more,
A liquid phase sintered aluminum alloy member having a tensile strength of 200 MPa or more.   The liquid phase sintered aluminum alloy member according to claim 7, wherein the surface roughness Rz is 6 or less.   The liquid phase sintered aluminum alloy member according to claim 7 or 8, wherein the perpendicularity is 0.1% or less of the total length.   The liquid phase sintered aluminum alloy member according to any one of claims 7 to 9, wherein the aluminum alloy is an Al-Si-Mg-Cu-based alloy.   The liquid phase sintered aluminum alloy member according to any one of claims 7 to 10, comprising hard particles made of a nonmetallic inorganic material and dispersed in a parent phase made of the aluminum alloy.

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