JP2005054231A - Aluminum composite material, parts for machine structure, and method for forming extruded material made of aluminum alloy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum composite material which has superior scuffing resistance and abrasion resistance, and shows superior extrusion characteristics; part items for machine structure; and a method for forming an extruded material made of an aluminum alloy. <P>SOLUTION: The aluminum composite material comprises the aluminum alloy 10 and hard particles 20. The aluminum alloy 10 includes, by mass%, 3% to 9.5% iron (Fe), 1% to 6% copper (Cu), 0.3% to 3% magnesium (Mg), and more than 0 but less than 1 mass% silicon (Si). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention generally relates to a method for forming an aluminum composite material, a machine structural component, and an aluminum alloy extruded material. More specifically, the present invention relates to a method of forming an aluminum composite material containing a large proportion of hard particles, a machine structural component, and an aluminum alloy extruded material.

  Conventionally, a rapidly solidified powder Al—Fe-based aluminum alloy containing a large amount of iron exhibits excellent strength characteristics at high temperatures, and an Al-8Fe alloy containing iron at a rate of 8 mass% is known. Such an aluminum alloy is disclosed, for example, in JP-A-3-253536 (Patent Document 1).

Separately, it is known that hard particles such as alumina and silicon are added to an aluminum alloy, and a sleeve, a cylinder liner, and the like are formed from the aluminum alloy by a hot extrusion method. The sleeve and cylinder liner are incorporated into the engine and slide with the piston ring. By adding hard particles to the aluminum alloy, the hard particles in a state of protruding from the sliding surface of the sleeve or the cylinder liner come into contact with the sliding piston ring. For this reason, the wear resistance and scuff resistance of the sleeve and cylinder liner can be improved.
JP-A-3-253536

  The Al—Fe-based aluminum alloy exhibits excellent strength at temperatures exceeding 200 ° C., but the strength decreases at temperatures of 150 ° C. or lower compared to other alloys. Further, when forming a sleeve or a cylinder liner from an aluminum alloy by a hot extrusion method, the aluminum alloy is placed at a temperature of about 400 ° C. to 500 ° C. However, because of the high strength at high temperatures, heat-resistant aluminum alloys such as Al-8Fe alloys exhibit only about 20% or less elongation at that temperature.

  Since the elongation of the aluminum alloy is low in this way, if the amount of hard particles added is increased, there arises a problem that cracks occur in the aluminum alloy during extrusion molding. This is because if the addition amount of the hard particles is increased, the hard particles are easily aggregated in the aluminum alloy, and cracks are generated starting from the aggregated portion of the hard particles. However, the wear resistance and scuff resistance of sleeves and cylinder liners cannot be sufficiently improved only by adding hard particles within a range where there is no risk of cracking.

  Accordingly, an object of the present invention is to solve the above-described problems, and is formed of an aluminum composite material, a machine structural component, and an aluminum alloy extruded material that exhibit excellent wear resistance and scuff resistance characteristics and excellent extrusion characteristics. Is to provide a method.

  The aluminum composite material according to the present invention includes an aluminum alloy and hard particles. The aluminum alloy is 3% by mass to 9.5% by mass of iron (Fe), 1% by mass to 6% by mass of copper (Cu), and 0.3% by mass to 3% by mass with respect to the aluminum alloy. % Magnesium (Mg) or less and less than 1% by mass of silicon (Si). Here, the hard particles are those having a Vickers hardness of Hv 100 or more with respect to the matrix of the aluminum alloy. Preferably, the ratio of the hard particles to the aluminum composite material is 5 area% or more and 30 area% or less per unit area.

  The inventors have found that an aluminum alloy having such a metal composition exhibits high strength at temperatures from room temperature to about 200 ° C., and exhibits high elongation at temperatures of 400 ° C. or higher. Further, it has been found that according to this aluminum alloy, the above-mentioned characteristics can be obtained without performing a heat treatment for aging treatment.

  From such knowledge, the aluminum composite material formed from this aluminum alloy and hard particles exhibits high elongation at a temperature of 400 ° C. or higher. For this reason, even if it is a case where an aluminum composite material contains a hard particle, there is no possibility that a crack may arise at the time of extrusion molding of an aluminum composite material. On the other hand, the aluminum composite material exhibits high strength at temperatures from room temperature to about 200 ° C.

  The hard particles protrude from the surface of the aluminum composite material and suppress the direct contact between the surface of the aluminum composite material and a member that slides on the surface. When the ratio of the hard particles is 5 area% or more, such an effect can be sufficiently obtained. Moreover, when the ratio of a hard particle is 30 area% or less, the machinability of an aluminum composite material is favorable, and the extrusion characteristic of the aluminum composite material is not lowered due to the excessive ratio of the hard particle.

  For the reasons described above, according to the present invention, it is possible to realize an aluminum composite material that is excellent in wear resistance and scuff resistance and exhibits excellent extrusion characteristics.

  In addition, the aluminum alloy which consists of the above-mentioned metal composition is formed from the matrix in which aluminum is the main component and magnesium was dissolved, and the intermetallic compound which precipitated in the matrix. The intermetallic compound deposited in the matrix has a high strength and exists stably even at high temperatures. For this reason, the strength of the aluminum alloy is considered to be maintained even under high temperature conditions.

  Magnesium is dissolved in a matrix mainly composed of aluminum so as to have a concentration distribution along the dislocation strain field of the matrix. This magnesium tends to diffuse in the matrix at high temperatures. For this reason, when the aluminum alloy is plastically deformed at a high temperature, the magnesium moves as the matrix dislocations move.

  At this time, when the rate of plastic deformation of the aluminum alloy is low, the matrix dislocations and the magnesium can move at the same rate. However, when the rate of plastic deformation of the aluminum alloy is gradually increased, the rate at which magnesium can move becomes slower than the rate at which the matrix dislocations move. For this reason, when the aluminum alloy is plastically deformed at a high speed, resistance due to magnesium is generated according to the plastic deformation rate, and the elongation of the aluminum alloy can be improved. That is, it is considered that the strain rate sensitivity is improved by the solid solution of magnesium in the matrix, whereby the elongation of the aluminum alloy can be improved.

  More preferably, the aluminum alloy contains 6% by mass or more and 8.5% by mass or less of iron, 3.5% by mass or more and 4.5% by mass or less of copper, 1% by mass or more and 2% by mass or less of magnesium, And more than 0 and less than 1% by mass of silicon.

  Preferably, the aluminum alloy further includes 0.3% by mass or more and 4% by mass or less of manganese (Mn). According to the aluminum composite material thus configured, the hardness of the aluminum alloy can be improved. Thereby, when a load is applied to the hard particles from the outside, the amount of the hard particles sinking into the aluminum alloy can be reduced. When the proportion of manganese is 0.3% by mass or more, the hardness of the aluminum alloy can be sufficiently improved. Further, when the manganese ratio is 4% by mass or less, the hardness of the aluminum alloy does not become too high, and the machinability of the aluminum composite material does not significantly decrease. More preferably, the aluminum alloy further includes 2% by mass or more and 3% by mass or less of manganese.

  Preferably, the hard particles include at least one selected from the group consisting of mullite, FeMo, and porous amorphous carbon. The hardness of these materials is in the range of about Vickers hardness Hv500 to 1200. When the hardness of the hard particles is equal to or less than Hv 1200, the machinability of the aluminum composite material is not lowered, and the opponent attack against the external member in contact with the hard particles can be lowered. Further, when the hardness of the hard particles is Hv 500 or more, the self wear of the hard particles due to the contact between the external member and the hard particles can be suppressed.

  The porous amorphous carbon is obtained by impregnating various cellulose materials with a resin and carbonizing and firing a molded product obtained by compressing the resin. Examples of such porous amorphous carbon include wood ceramics using wood or woody materials as cellulosic materials, and rice bran ceramics using rice bran as cellulosic materials.

  Preferably, the hard particles have a particle size of 2 μm or more and 150 μm or less. When the particle size of the hard particles is 2 μm or more, the effect of embedding the hard particles in the aluminum alloy is sufficiently obtained. Further, the hard particles hardly aggregate and are uniformly dispersed in the aluminum alloy. For these reasons, it is possible to prevent the hard particles from being lost from the aluminum alloy as the hard particles are worn. When the particle size of the hard particles is 150 μm or less, the machinability of the aluminum composite material is not significantly reduced. Moreover, it becomes difficult to break hard particles against impact from the outside, and the problem that the hard particles are missing from the aluminum alloy due to cracking can be suppressed.

  The mechanical structural component according to the present invention is formed using the aluminum composite material described above. Mechanical structural parts containing hard particles at a predetermined ratio are excellent in wear resistance and scuff resistance for the reasons already described. In addition, it exhibits particularly high mechanical strength at temperatures from room temperature to about 200 ° C. Examples of such mechanical structural parts include sleeves and cylinder liners used in internal combustion engines, and other pump rotors. This aluminum composite material has a high elongation at 400 ° C. or higher, and is suitable for forming a sleeve, a cylinder liner, or the like with an extruded material.

  The method for forming an extruded material made of an aluminum alloy according to the present invention includes 3% by mass to 9.5% by mass of iron, 1% by mass to 6% by mass of copper, 0.3% by mass to 3% by mass of copper. A step of forming a molded body by forming a mixture of magnesium and an aluminum alloy containing silicon that is greater than 0 and less than 1% by mass, and hard particles, and extruding the molded body at a temperature of 400 ° C. or higher. Forming an extruded material made of aluminum alloy.

  According to the method of forming an aluminum alloy extruded material thus configured, the aluminum alloy exhibits high elongation at a temperature of 400 ° C. or higher. Therefore, the aluminum alloy formed at the time of extrusion molding under this temperature condition is made. There is no cracking in the extruded material. For this reason, the ratio of the hard particles contained in the molded body can be increased to obtain an aluminum alloy extruded material excellent in wear resistance and scuff resistance. In addition, in the process of extruding the molded body, the extrusion speed can be improved. Thereby, the production efficiency of the extruded material made of aluminum alloy can be improved. Preferably, the step of forming the formed body is a step of mixing the aluminum alloy and the hard particles so that the ratio of the hard particles to the aluminum alloy extruded material is 5% by area or more and 30% by area or less per unit area. including.

  As described above, according to the present invention, it is possible to provide an aluminum composite material, a machine structural component, and an aluminum alloy extruded material that have excellent wear resistance and scuff resistance characteristics and exhibit excellent extrusion characteristics. Can do.

  Embodiments of the present invention will be described with reference to the drawings.

  1 and 2 are photomicrographs showing the surface of an aluminum alloy extruded material according to an embodiment of the present invention. The magnification of the micrograph shown in FIG. 1 is 50 times, and the magnification of the micrograph shown in FIG. 2 is 400 times. A cylinder liner and a sleeve that are incorporated into the engine and slide with the piston ring are manufactured by lathing or the like on the extruded material made of aluminum alloy shown in FIGS. 1 and 2.

  Referring to FIGS. 1 and 2, the aluminum alloy extruded material is formed of aluminum alloy 10 and hard particles 20 dispersed and distributed in aluminum alloy 10. The hard particles 20 are made of rice bran ceramic. The ratio in which the hard particles 20 are contained is 5 area% or more and 30 area% or less with respect to the aluminum alloy extruded material. The fine line shape from the upper edge to the lower edge in the figure is formed at the time of extrusion molding of the extruded material made of aluminum alloy.

  The aluminum alloy 10 is composed of 3% by mass to 9.5% by mass of iron, 1% by mass to 6% by mass of copper, and 0.3% by mass to 3% by mass of magnesium with respect to the aluminum alloy 10. And more than 0 and less than 1% by mass of silicon, the balance being aluminum and inevitable impurities.

  FIG. 3 is a graph showing the relationship between the tensile strength and temperature of the aluminum alloy in FIG. 3 includes 8% by mass of iron, 4% by mass of copper, 1.5% by mass of magnesium, and inevitably small amounts of silicon as the aluminum alloy in FIG. Contains aluminum and aluminum alloy A, which is an unavoidable impurity, and 4% by mass of iron, 4% by mass of copper, 1.5% by mass of magnesium, and an inevitable amount of silicon, with the balance being aluminum The relationship between the tensile strength of aluminum alloy B, which is an unavoidable impurity, and temperature is shown.

  For comparison, a # 217 alloy containing 17% by mass of silicon, 5% by mass of iron, 3% by mass of copper, and 1.5% by mass of magnesium, with the balance being aluminum and inevitable impurities, Also shown is the relationship between the tensile strength and temperature of an Al8Fe alloy containing 8% by mass of iron and the balance of aluminum and inevitable impurities.

  Referring to FIG. 3, aluminum alloys A and B have a tensile strength equal to or higher than that of # 217 alloy and Al8Fe alloy in a temperature range from room temperature to about 300 ° C., and particularly 350 MPa even at a temperature of about 250 ° C. The above tensile strength is maintained. For this reason, the aluminum alloy extruded material formed from the aluminum alloy 10 exhibits excellent strength characteristics even at a temperature of about 200 ° C. where the cylinder liner and the sleeve are placed.

  4 is a graph showing the relationship between elongation at break and temperature of the aluminum alloy in FIG. FIG. 4 also shows the relationship between the elongation at break and the temperature of # 217 alloy and Al8Fe alloy for comparison, in addition to aluminum alloys A and B as the aluminum alloys in FIG.

  Referring to FIG. 4, the breaking elongation of # 217 alloy and Al8Fe alloy has a value of 20% or less regardless of temperature change, whereas the breaking elongation of aluminum alloys A and B is 200 ° C. It increases rapidly at temperatures exceeding. As a result, at a temperature of 400 ° C., the elongation at break exceeds 50%. For this reason, even when the aluminum alloy extruded material formed from the aluminum alloy 10 contains a large amount of hard particles 20, it exhibits excellent extrusion characteristics during extrusion molding performed at a temperature of 400 ° C. or higher.

  FIG. 5 is a graph showing the hardness of hard particles made of various materials. Referring to FIG. 5, mullite has a Vickers hardness of about 1150, FeMo has a Vickers hardness of about 1100, and rice bran ceramic has a Vickers hardness of about 600. Here, the Vickers hardness of the hard particles 20 is preferably 500 or more and 1200 or less.

  Since the aluminum alloy extruded material thus configured has excellent extrusion characteristics, it can contain the hard particles 20 at a ratio of 5 area% or more. For this reason, when a cylinder liner and a sleeve are manufactured with this aluminum alloy extruded material, more excellent wear resistance and scuff resistance can be obtained. Moreover, since the ratio in which the hard particle | grains 20 are contained is 30 area% or less, it can prevent that the machinability and extrusion characteristic of an aluminum alloy extrusion material fall.

  In order to evaluate the aluminum composite material according to the present invention, a seizure evaluation test and an abrasion resistance evaluation test were performed according to the procedures described below.

  First, the aluminum alloy of Sample 1 containing 8% by mass of iron, 4% by mass of copper, 1.5% by mass of magnesium, and inevitably a small amount of silicon, the balance being aluminum and inevitable impurities Contains powder, 8 mass% iron, 4 mass% copper, 1.5 mass% magnesium, 2 mass% manganese, and unavoidable traces of silicon with the balance being aluminum and inevitable The aluminum alloy powder of Sample 2, which is an impurity, 8% by mass of iron, 4% by mass of copper, 1.5% by mass of magnesium, 3% by mass of manganese, and inevitable amounts of silicon The balance is aluminum and the aluminum alloy powder of sample 3 which is unavoidable impurities, 4% by mass of iron, 4% by mass of copper, 1.5% by mass of magnesium, And a silicon, the balance was prepared an aluminum alloy powder of Sample 4 is aluminum and inevitable impurities. Separately, three types of hard particles were prepared: mullite (average particle size 12 μm), wood ceramic (average particle size 20 μm), and FeMo (average particle size 30 μm).

The aluminum alloy powders of Samples 1 to 4 and three types of hard particles were appropriately combined and mixed for 15 minutes with a V-type brenter. At this time, the ratio of the hard particles to be combined was changed from 10 area% to 20 area% per unit area. The powder obtained by mixing was molded at a molding pressure of 5 × 10 ³ (kgf / cm ² ) to form a molded body. The molded body was heated to a temperature of 460 ° C. and then extruded into a round bar having a diameter of 22 mm. At this time, no crack was observed in any of the round bars.

  FIG. 6 is a side view showing the shape of the test piece. Referring to FIG. 6, a test piece 31 having a size of 5 mm × 10 mm × 7 mm and a chamfered surface of C 0.5 mm was cut out from the round bar. Thus, test pieces 31 of Examples 1 to 13 in which the combination of the aluminum alloy powder and the hard particles and the ratio of the hard particles were different were produced. Separately, in order to confirm the effect of the present invention, test pieces of Comparative Examples 1 to 3 made of an aluminum alloy in which hard particles are not mixed were prepared. The composition of these test pieces is shown in Table 1.

  FIG. 7 is a side view showing a chip-on-disk test apparatus. Using the apparatus shown in FIG. 7, a test piece seizure evaluation test was performed. Referring to FIG. 7, nitrided steel (φ60 mm × 7 mm) having a nitrided surface was used as the counterpart material 32 against which the test piece 31 was pressed. The test was performed in two types: a dry type in which the test piece 31 is directly pressed against the surface of the counterpart material 32 and a wet type in which 0.05 mg of oil is dropped onto the surface of the counterpart material 32 and the test piece 31 is pressed.

  The mating member 32 was fixed to the rotating member 34, and the test piece 31 was fixed to the fixing member 33. The test piece 31 was pressed against the mating member 32 with a load of 0.04 MPa. In this state, the test was started by rotating the rotary member 34 with respect to the fixed member 33 at a speed of 0.25 m / s.

  The time until the frictional resistance between the test piece 31 and the mating member 32 changes was measured, and that time was taken as the scuffing time (evaluation of initial scuffing). Scuffing refers to a phenomenon in which sliding surfaces are welded to each other. Separately, the load for pressing the test piece 31 was increased stepwise, and the load when seizure occurred was defined as the seizure load. Table 1 shows the measured scuff generation time and seizure load.

  Next, an abrasion resistance evaluation test of the test piece was performed using the apparatus shown in FIG. In this test, the contact portion between the test piece 31 and the counterpart material 32 was immersed in oil, and the test piece 31 was pressed against the counterpart material 32 with a load of 100 MPa. In this state, the test was started by rotating the rotating member 34 relative to the fixed member 33 at a speed of 0.25 m / s. The amount of wear of the test piece 31 after 1 hour from the start was measured, and this is shown in Table 1 as the amount of self-wear. At the same time, the wear amount of the mating member 32 was measured, and this was shown in Table 1 as the mating wear amount.

  Referring to Table 1, when the test piece of Comparative Example 1 and the test pieces of Examples 1 to 7, 12 and 13 were compared, the scuff generation time in the test pieces of Examples 1 to 7, 12 and 13 was It was confirmed that it was a relatively long time. Further, when the test pieces of Comparative Examples 1 to 3 and the test pieces of Examples 1 to 13 were compared, it was confirmed that the seizure load was relatively large in the test pieces of Examples 1 to 13. . Further, when the test pieces of Comparative Examples 1 to 3 and the test pieces of Examples 1 to 13 are compared, the amount of self-wear of the test piece 31 is relatively small in the test pieces of Examples 1 to 13. Was confirmed.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a microscope picture which shows the surface of the aluminum alloy extrusion material in embodiment of this invention. It is another microscope picture which shows the surface of the aluminum alloy extrusion material in embodiment of this invention. It is a graph which shows the relationship between the tensile strength of aluminum alloy in FIG. 1, and temperature. It is a graph which shows the relationship between the breaking elongation of aluminum alloy in FIG. 1, and temperature. It is a graph which shows the hardness of the hard particle which consists of various materials. It is a side view which shows the shape of a test piece. It is a side view showing a chip on disk test device.

Explanation of symbols

  10 Aluminum alloy, 20 hard particles.

Claims (8)

Comprising aluminum alloy and hard particles,
The aluminum alloy is 3% by mass to 9.5% by mass of iron, 1% by mass to 6% by mass of copper, and 0.3% by mass to 3% by mass of magnesium with respect to the aluminum alloy. And an aluminum composite material comprising more than 0 and less than 1% by mass of silicon.   The aluminum composite material according to claim 1, wherein a ratio of the hard particles to the aluminum composite material is 5 area% or more and 30 area% or less per unit area.   The aluminum composite material according to claim 1, wherein the aluminum alloy further contains 0.3% by mass or more and 4% by mass or less of manganese.   The aluminum composite material according to any one of claims 1 to 3, wherein the hard particles include at least one selected from the group consisting of mullite, FeMo, and porous amorphous carbon.   The aluminum composite material according to any one of claims 1 to 4, wherein a particle diameter of the hard particles is 2 µm or more and 150 µm or less.   A machine structural part formed using the aluminum composite material according to claim 1. Aluminum containing 3% by mass or more and 9.5% by mass or less of iron, 1% by mass or more and 6% by mass or less of copper, 0.3% by mass or more and 3% by mass or less of magnesium, and more than 0 and less than 1% by mass of silicon Forming a molded body by molding a mixture of an alloy and hard particles;
Forming the aluminum alloy extruded material by extruding the molded body at a temperature of 400 ° C. or higher.   In the step of forming the formed body, the aluminum alloy and the hard particles are mixed so that the ratio of the hard particles to the extruded material made of the aluminum alloy is 5 area% or more and 30 area% or less per unit area. The shaping | molding method of the aluminum alloy extrusion material of Claim 7 including a process.