JPH0448858B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to an aluminum alloy that is lightweight, has high strength comparable to that of steel, and has wear resistance superior to Alzyl alloy, and a method for producing the same. (b) Background of the technology Aluminum alloys are lighter than steel and have superior corrosion resistance, so they are expected to be a metal material that will contribute to improving the fuel efficiency of transportation equipment and portability of office equipment. However, conventional aluminum alloys such as duralumin and ultra-super duralumin have high strength but poor wear resistance, so that their use as structural parts is extremely limited. On the other hand, hypereutectic or eutectic Al-Si alloys are known as wear-resistant aluminum alloys. This alloy is
Since it has a structure in which primary crystals of Si are dispersed in the matrix, it has been put into practical use due to its significantly improved wear resistance. However, the primary crystals of this alloy are coarse, over 100 μm, so machinability is extremely poor, and the addition of Si makes the molten metal viscous.
Because of the poor fluidity, it was difficult to produce sound castings, and there were many manufacturing problems. Furthermore, the conventional limit for the Si content in Al-Si alloys has been around 17%, and although it is expected that wear resistance can be further improved by increasing this, in reality, this is completely impossible with the melting method. It was hot. For this reason, powder metallurgy methods are being considered, and there is an example of trial production of Al-35%Si material.
In this method, by producing Al-Si alloy powder by atomization, the cooling rate is more than 1000 times faster than ingot cooling, making it possible to make the primary crystals of Si fine. However, although this alloy has excellent wear resistance, it has low strength and is brittle, making it unsatisfactory as a practical material. Next, it was expected that high strength and wear resistance would be improved by using a duralumin-based alloy as a matrix, but this method alone would result in Si being dissolved in the matrix, completely disrupting the balance of the original duralumin structure. The strength of the alloys obtained has not been substantially improved. (C) Disclosure of the Invention The present invention solves these conventional problems by creating an aluminum alloy powder with the same alloy structure that originally provides high strength for matrix alloys, and mixing sufficiently fine Si powder with this powder. However, by hot extrusion in a temperature range where Si does not cause a eutectic reaction with Al, Si particles coherently adhere to the Al alloy matrix, making it possible to manufacture an ideal composite material. This is what I found. The matrix alloy composition of the alloy of the present invention includes Zn, Cu, Mn, which is the composition of high-strength duralumin,
In addition to Al alloys containing Cr, Ni, Ti, Zr, Fe, Co, which are effective in improving heat resistance and corrosion resistance,
An Al alloy containing Mo is desirable. There are many systems for optimal combinations of these alloying elements, e.g.
7075 series Al−1.6Cu−2.5Mg−0.25Cr−5.5Zn,
7091 series Al−1.5Cu−2.5Mg−0.3Co−6.4Zn, and ultra-high strength Al−10Zn−4Mg−0.8Cu−1.2Mn
−1Fe−1.4Ni and heat-resistant type Al−8Fe−2Co,
There are Al-Zr, Al-Ni, etc. In any of these alloy systems, the method of the present invention makes it possible to obtain high strength without disturbing the structural balance of the optimum composition. A requirement of the present invention is to prevent Si from forming a solid solution in the matrix. Experiments have shown that if the solid solution amount of Si as an impurity is 0.5% by weight or less, a good quality alloy can be obtained without causing matrix embrittlement. The matrix alloy is as described above, and it is necessary to use this alloy powder. Next, the particle size of Si to be dispersed is preferably at least 50 μm or less. In ordinary casting materials, the Si particle size is 100μ or more, and from the viewpoint of strength, machinability, etc., the Si particles need to be fine. It is preferable from the viewpoint of diffusion reaction. Further, the amount of Si particles dispersed is preferably in the range of 30 to 50% by weight in view of the balance between wear resistance and strength. Si is
If it is less than 30%, wear resistance will be insufficient, and if it is more than 50%, toughness will decrease. The alloy of the present invention has a content of 30 to 50% in the above-mentioned Al alloy powder.
Manufactured by mixing Si particles with a weight percent of 50μ or less, forming this into a block using static pressure molding, etc., and hot extruding at a temperature range where Si does not cause a eutectic reaction with Al. I can do it. This will be explained below using examples. Example 7075 series Al alloy was melted to obtain -40 mesh atomized alloy powder. The amount of Si solid solution in the obtained powder was 0.3%. After adding and mixing 35% by weight of -325 mesh (47μ) Si crushed powder to this alloy powder, it was molded into ^a φ70×
It was molded into a 300mm round bar. After inserting this into a copper container and closing the lid, it was heated to 500°C and extruded into a round bar using a hot extruder with a cross-section reduction rate of 80%. The extruded rod is immediately quenched and solution treated, then 10×
It was machined into a rectangular parallelepiped of 10 x 50 mm and a round bar of φ8 x φ4 x 50 mm, and subjected to an Okoshi type abrasion test and a tensile test.
As a comparison material, a test piece was prepared by cutting the cast material AC8A to the same dimensions, and the test was conducted in the same manner. 1st
The table shows the results of this test, and it is clear that the alloy of the present invention has excellent strength and wear resistance. The specific wear amount in the table is 6.6Kg for pressure P and 3m/3 for speed V.
These are the results of a dry abrasion test at a wear distance L of 200 m. Figure 1 is a 400 times magnified microscopic photograph of the alloy of the present invention, showing that Si particles (gray) are uniformly dispersed in the matrix. This alloy also had good machinability when cutting out test pieces. 【table】

[Brief explanation of drawings]

FIG. 1 is a 400 times enlarged micrograph of the microstructure of an example of the alloy of the present invention.

Claims (1)

[Claims] 1. Zn, Cu, Mg, Mn, Cr, as alloying elements
Contains 5 to 20% by weight of one or more selected from Ti, Zr, Fe, Co, Ni, and Mo, and has a solid solution amount of Si of 0.5
1. A high-strength, wear-resistant aluminum alloy characterized by having an aluminum alloy matrix having a weight percent or less, and 30 to 50 weight percent of Si particles having a grain size of 50 μ or less dispersed in the matrix. 2 Zn, Cu, Mg, Mn, Cr, as alloying elements
Contains 5 to 20% by weight of one or more selected from Ti, Zr, Fe, Co, Ni, and Mo, and has a solid solution amount of Si of 0.5
A high-strength product characterized by using aluminum alloy powder of 30% by weight or less, mixing 30 to 50% by weight of Si powder with a particle size of 50μ or less, preforming, and then hot extruding at a temperature of 500℃ or less. Manufacturing method of wear-resistant aluminum alloy.