JPH02149633A - Low thermal expansion aluminum alloy having excellent wear resistance and heat conductivity - Google Patents

Abstract

PURPOSE:To obtain the title Al alloy having excellent wear resistance and heat conductivity and having low thermal expansion coefficient by adding specific amounts of Ni, Si, Cu, Mg and other metallic elements to Al. CONSTITUTION:The molten metal of an Al alloy of which, by weight, 10 to 30% Ni, 15 to 30% Si, 0.5 to 2% Cu and 0.3 to 2% Mg or furthermore one or more kinds among 0.01 to 1% Cr, 0.01 to 1% Mn, 0.01 to 0.5% Zr, 0.01 to 0.1% V, 0.01 to 1% Ti, 0.01 to 5% Zn and 0.01 to 5% Fe is poured into a mold heated to the liquidus of the Al alloy +100 deg.C and is cooled to solidify under pressure into a billet. The billet is extruded into a round bar or the like, which is subjected to solution heat treatment, is thereafter water-cooled and is successively subjected to aging treatment, by which the Al alloy material having excellent wear resistance and heat conductivity and having low thermal expansion coefficient can be manufactured.

Description

[Detailed Description of the Invention] Industrial Application Fields The present invention is used for, for example, cylinders, vanes, automobile parts and various mechanical parts that have a small geothermal expansion coefficient and are required to have wear resistance and thermal conductivity. This invention relates to a low thermal expansion aluminum alloy with excellent wear resistance and thermal conductivity.

Conventional technology Conventionally, this type of aluminum alloy was AQ-3L, which added Si as an element to improve wear resistance.
aluminum alloys are well known,
Commonly used.

Problems to be Solved by the Invention However, when increasing the amount of Si added to improve wear resistance, the wear resistance improves and the coefficient of thermal expansion decreases, but the castability, machinability, and forgeability deteriorate. There is a problem that the amount of addition is naturally limited.

In view of these circumstances, the present invention aims to provide an aluminum alloy that has excellent mechanical properties such as wear resistance, excellent physical properties such as thermal conductivity and low thermal expansion, and has good extrudability. It was done for a purpose.

As a means to solve the problem, this invention was developed as a result of intensive research, and by dispersing Al3Ni intermetallic compound in addition to hard particles of Si, and at the same time coexisting Cu and Mg,
It was discovered that it was possible to sufficiently improve wear resistance and thermal expansion properties, and at the same time improve thermal conductivity, castability, machinability, and forgeability, and was able to complete it based on this knowledge. It is.

That is, the first aspect of the present invention contains Ni: 10 to 30%, Si: 15 to 30%, Cu: 0.5 to 2%, Mg: 0.3 to 2%, and the remainder is resistant to Ω and unavoidable impurities. A low thermal expansion aluminum alloy with excellent wear resistance and thermal conductivity.

Furthermore, the second invention provides, in addition to the essential elements 5iSNi, Cu and Mg of the first invention, Cr: 0.01-1% Mn: 0. 01-1% Zr: 0.01-0.5% V: 0.01-0.1% Ti: 0.01-1% Z'n: 0. It is a low thermal expansion aluminum alloy containing one or more of the following: 0.01-5% Fe: 0.01-5%, and the remainder consisting of ρ and unavoidable impurities, and has excellent wear resistance and thermal conductivity.

In this specification, "96" indicates "weight 96".

The significance of the above-mentioned alloy additive elements and the reason for limiting their content are as follows.

That is, Ni forms an Al3Ni intermetallic compound and is dispersed in the alloy, which mainly contributes to improving wear resistance and lowering the coefficient of thermal expansion, and if its content is less than 10%, the above effects are poor. If the content exceeds 30%, coarse intermetallic compounds are formed and machinability is deteriorated.

A particularly preferable content is about 12 to 25%.

St improves wear resistance and strength as well as lowers the coefficient of thermal expansion. If it is less than 15%, sufficient effects may not be obtained depending on the application, and if it exceeds 30%, the machinability, especially the life of the cutting tool, may be reduced. to degrade. A particularly preferable content is about 20 to 25%.

Both Cu and Mg are used to increase strength, and when Cu is less than 0.5% and Mg is less than 0.3%, this effect is small, and conversely, when Cu and Mg are more than 2%, In this case, extrusion processability deteriorates. Particularly preferable contents are 1.0 to 1.5% in CU and 0 in Mg.
It is about 5 to 1.5%.

Cr, Mn, Zr, V, Ti, and ZnSFe all have the effect of improving the mechanical properties of the alloy, and in this invention, they are evaluated as equivalent to each other in terms of the effect of addition. be. If the individual content of any of them is less than 0.01%, it is insufficient to realize the above effect, and conversely, if the content exceeds the specified value and is excessively contained (Cr, Mn
ST l: more than 1%, Zr: more than 0.5%, V: 0.
If the content is more than 1%, Zn, Fe: more than 5%), the above effects are saturated and no other particularly beneficial effects are produced.

Incidentally, the alloy of the present invention is suitably manufactured by a pressure solidification method. This pressure coagulation method will be explained as follows. That is, by melting the alloy of the present invention and pouring the molten metal into a pressure solidification mold and solidifying it under pressure, a billet with uniform and fine crystal grains without defects is created. The pressurized solidification mold may utilize a container of an extruder. That is, the molten aluminum alloy may be directly poured into the container and solidified while being pressurized by the stem. Of course, in this case, it is necessary to close the front surface of the container with a blind die to prevent the molten metal from blowing out during pressurized solidification.

In addition, when pouring the metal, prepare the mold with a diameter of 300 to 350.
It is desirable to heat it to about ℃. This makes it possible to obtain a finer texture in the billet. That is, if the temperature is less than about 300° C., solidification of the aluminum will start immediately after pouring, making it difficult to fully achieve the effect of pressure solidification. On the other hand, if it is heated to a high temperature exceeding 350° C., the cooling rate slows down, and crystallized substances tend to grow, making it difficult to sufficiently achieve the above-mentioned refinement effect. Immediately after pouring the molten metal, the molten metal in the mold is pressurized by a pressurizing piston to advance solidification, thereby creating a billet. That is, a billet is created by a pressure coagulation method. The pressing force at this time should be 50A9f/cn1 or more, preferably 3f/cn1 in the range of 500 to 1000.
It is preferable to set it to about al. The magnitude of this pressing force does not significantly affect the quality of the billet. However, if it is less than 50 to 9 f/d, the effect of preventing casting cracks and refining crystal grains by the pressure solidification method is insufficient;
On the other hand, even if a high pressure of more than 150 ONgf/cd is applied, for example, it is rather useless because the effect cannot be proportionally improved commensurate with the increase in energy required. In this way, by solidifying the aluminum alloy under a predetermined pressurized state, a small billet of crystallized material can be created without causing casting cracks.

The billet produced by the above pressure solidification method is then extruded to form the desired aluminum alloy material. Here, the billet may be used in a solid state that has been cooled once, but preferably, the temperature of the billet is adjusted to a temperature suitable for extrusion processing, for example, about 1/2 of the liquidus temperature, by the progress of the pressure solidification. It is recommended that the pressurized solidification process be completed when the temperature has decreased to a certain degree and the mixture has reached a semi-molten state, and that the extruder be immediately loaded into the container of the extruder and extrusion be started. By adopting such a procedure, it is possible to omit the billet heating step during extrusion processing, saving the energy and time required for heating, improving the manufacturing efficiency of alloy extrusions, and reducing manufacturing costs. can enjoy benefits.

Effects of the Invention As is clear from the following examples, the aluminum alloy according to the present invention has a lower St content than a comparative alloy in which one or more of the alloy compositions deviates from the range of the limitations of the alloy composition. Despite the limitations, it is possible to achieve the effect of further improving wear resistance, thermal conductivity, and low thermal expansion.

Examples For each of the present invention alloy and comparative alloy shown in Table 1, the molten metal is poured into a pressure solidification mold heated to the liquidus temperature +100°C, and solidified under a pressure of 1000 Kyf/ad to form a billet. and extrude this billet at a temperature of 49
Extruded into a round bar with a diameter of 121!1m at 0℃,
A sample material was obtained by solution treatment at 6 hours at ℃, cooling with water, and aging treatment at 200 ℃ for 12 hours.

The abrasion resistance, thermal conductivity, and coefficient of thermal expansion of each sample material were then examined. The results are shown in Table 2.

The abrasion resistance test was conducted using an Okoshi type abrasion tester with a rotating disk, load: 2.1 to 9, friction distance: 60
0m, friction speed: 3.67m/S1 mating material: FC-3
0 (JIS), test surface: Emery Paper 1200
The evaluation was made by measuring the specific wear amount of the sample material when it was rubbed under the test conditions of 1.

[Margin below]

As shown in the results in Table 2 above, the alloy of the present invention has much improved wear resistance, as well as improved thermal conductivity and low thermal expansion, compared to the comparative alloy. I was able to confirm that.

that's all

Claims (2)

[Claims] (1) Contains Ni: 10-30% Si: 15-30% Cu: 0.5-2% Mg: 0.3-2%, with the remainder being Al and inevitable impurities, which has good wear resistance and thermal conductivity. Superior low thermal expansion aluminum alloy. (2) Contains Ni: 10-30% Si: 15-30% Cu: 0.5-2% Mg: 0.3-2%, and Cr: 0.01-1% Mn: 0.01 -1% Zr: 0.01-0.5% V: 0.01-0.1% Ti: 0.01-1% Zn: 0.01-5% Fe: 0.01-5% A low thermal expansion aluminum alloy with excellent wear resistance and thermal conductivity, containing one or more of these, the remainder being Al and unavoidable impurities.