JPH0428835A - Manufacture of particle dispersed composite - Google Patents

Abstract

PURPOSE:To manufacture a composite by a simple process by pressurizing and infiltrating the molten metal of a low melting allay into the space among preheated ceramic particles having specified particle size, remelting and stirring it and thereafter executing casting. CONSTITUTION:Preheated ceramic particles 1 having 0.1 to 1000mum particle size is housed in a heated die 2, and then, the molten metal 5 of a low melting alloy such as an Al allay is poured therein. Between upper and lower punches 3 and 4, 100 to 10000kg f/cm<2> pressure is applied to infiltrate the molten metal 5 into the space among the ceramic particles 1, by which a composite 6 is manufactured. This composite 6 is again heated and melted, and the obtd. molten metal 7 is housed in a melting furnace 11 provided with a stirring bar 10, is stirred and is thereafter cast by a mold. In this way, its manufacturing cost can be reduced. Furthermore, even ceramic particles having small particle size can easily be compounded.

Description

[Detailed Description of the Invention] a. Industrial Application Field The present invention relates to AN, Zn, Mg, Sn, Pb, B
A low alloy material such as i is used as a matrix, and Si is added to it.
C, Al! 03SiJ4. The present invention relates to a method for manufacturing a particle-dispersed composite material (1'1MC) in which ceramic particles such as C are dispersed.

b. Conventional technology Regarding composite materials, the following conventional techniques are known.

For example, after making a preform using fibers and whiskers such as SiC or C, and inserting this into a mold, AI
! This is a method of making a composite material (FRM) by pouring a molten metal such as an alloy into a preform and impregnating it under pressure.

There is also a composite casting method in which particles of SiC, C, etc. are added to a completely or partially melted molten metal, and this is mechanically stirred to form a composite material (M?lC).

Furthermore, a method (powder metallurgy) of mixing particles of SiC, C, etc. with powder of A1 alloy, etc. and manufacturing a composite material by hydrostatic compression, hot extrusion, sintering, etc. is widely used.

In addition, by mixing particles such as SiC or C with powder such as A1 alloy and giving it hot mechanical stirring, S
There is a method (mechanical alloying method) in which particles such as iC and C are kneaded into a particle-dispersed composite material.

Problems to be Solved by the C0 Invention Fibers and whiskers such as SiC and C are expensive, and manufacturing a preform using them is labor-intensive, resulting in high product costs.

In addition, in the above-mentioned composite casting method, even if particles with good wettability are added to the molten metal, the addition ratio to the molten metal must be 20 wt in order to evenly and uniformly disperse the particles.
% is the upper limit, and it is difficult to add more than this.

Furthermore, the alloy powder used in powder metallurgy is difficult to manufacture, therefore expensive, and requires many steps to complete as a composite material.

Since it is manufactured by extrusion, there is a problem in that it is limited to simple shapes.

In addition, the alloy powder used in the mechanical alloying method is expensive as mentioned above, the mixing ratio is limited to about 50 wt%, and an extrusion process is required to manufacture the product, which has the same problems as the powder metallurgy. be.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a method for producing a particle-dispersed composite material that solves the above-mentioned problems.

d. Means for Solving the Problems In accordance with the above objects, the present invention provides preheated particles with a diameter of 0.1 to 1.
000 μ- ceramic particles and a molten metal of a low alloy metal are placed in a mold and pressurized at a pressure of 100 to 100,100 O0/cd to allow the molten metal to infiltrate between the ceramic particles, and then immediately remelted. The above problem was solved by stirring and casting.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In the present invention, SiC, A
Ceramic particles such as 1 tox, 5isNa, and C are used. Particle size (average particle size) is 0.1 to 100
If the zero particle diameter is less than 0.1 μm, the cost is high and it is difficult to form a uniform composite. On the other hand, if the particle size exceeds 1000 .mu.-, the composite material can be easily formed, but the elongation and toughness of the manufactured composite material will be low, which is not preferable.

Now, in order to first remove moisture from SiC particles with an average particle diameter of 1 μm and improve impregnation with the molten metal to be added (described later),
For example, it overheats at a temperature of around 800°C. The heating temperature of the ceramic particles should be 600"C to 1000°C. If the temperature is less than 600°C, there is a risk of solidifying the molten metal that comes into contact with it, and if it exceeds 1000°C, it will take a long time for the molten metal to solidify, which is undesirable. .

In addition, the particles and molten metal introduced before compounding come into contact with the mold,
The mold is heated to a temperature of 200°C to 400°C to prevent that part from cooling and solidifying.

First, as shown in FIG. 1(a), for example, at about 300°C
A zero-order low alloy metal, such as JIS AC8^^1 alloy, containing the ceramic particles, that is, SiC particles 1, is heated and melted at about 750°C in a mold 2 which is heated, and this molten metal 5 is heated and melted. As shown in Figure 1), the metal is poured into a mold 2 containing SiC particles.

Note that the low-alloy metal here refers to an alloy with a melting point of 660°C or lower (lower than the melting point of Al), such as AI! IZn+Mg.

An alloy containing 70% or more of Sn, Pb, Bi, etc.

Then, as shown in FIG. 1(C), between the upper punch 3 and the lower punch 4, the
A pressure P of d, in this example, 100100 O/cj is applied, and the molten metal 5 is infiltrated into the gaps between the SiC particles 1,
Composite material (MMC) 6 is manufactured. In this case, some portions remain as the molten metal 5, and the SiC particles 1 are not evenly mixed.

Note that if the pressure is less than 100 kgf/d, the molten metal will not penetrate sufficiently into the voids between the ceramic particles,
Even if pressure is applied, no significant effect can be obtained.

If the pressure exceeds 100,100 O0/cii, the material becomes too hard and has an adverse effect on particle dispersion by stirring in the subsequent step, making it impossible to achieve a good dispersion state.

Next, in the above step, since the SiC particles are not yet uniformly dispersed in the matrix alloy, the SiC particles are redistributed again at the melting point and
In this example, the molten metal 7 is melted by heating to a temperature around 750'C, and as shown in FIG. After a period of 1 to 120 minutes, approximately 30 minutes in this example, casting into a mold is sufficient.

Note that when the particle size is large, the dispersibility is good, so the stirring time is short, and when the particle size is small, long stirring is required. The reason why the rotational speed of the stirring rod 10 is set in the above range is because if the rotation is slow, the efficiency of compounding is poor, and if the rotation is too fast, the stirring rod supported at one end will shake, causing the molten metal to scatter.

FIG. 3 shows the metallographic structure of a particle-dispersed composite material in which 15-t% of SiC particles of steel with an average particle diameter of 1 μm are composited using AC34 alloy as a matrix by the above method. According to the figure, it can be seen that black SiC particles are evenly dispersed in the 8A alloy on the white background A.

In addition, in the above embodiment, FIGS. 1(a) and (b)
As shown in , the ceramic particles are housed in the mold and then
Although the process sequence is to pour the molten metal, the molten metal may be placed in a mold, and then ceramic particles may be added and pressurized.

Further, instead of the rotational stirring of the molten metal, ultrasonic vibration may be applied to the molten metal to uniformly disperse the ceramic particles in the matrix alloy.

This is carried out via an arm to the crucible containing the molten metal.
It transmits ultrasonic vibrations of 0 kHz, and uses these vibrations to disperse particles more uniformly and break up particle agglomerates.

As another example, Al zoz with an average particle size of 10 μ-
Using particles, heated to a temperature of 800°C, housed in a mold, and then heated to a temperature of 750°C.
Molten AZ91C was poured into this and a pressure of 100,100 O/cj was applied to form a composite, which was again heated and melted at 750°C and stirred for 30 minutes to obtain a homogeneous composite material.

e. Effects of the Invention According to the method of the present invention, compared to conventional methods, it uses a simpler process and is manufactured by a casting method, so the product cost can be lower than that of products manufactured by various conventional methods. , ceramic particles with small particle sizes can also be easily composited.

[Brief explanation of drawings]

Figures 1 (a) to (C) are diagrams for explaining the procedure for producing the material according to the present invention, Figure 2 is a diagram for explaining the procedure for the continuous stirring process, and Figure 3 is for explaining the method for producing the material according to the present invention. A microscopic photograph of the metal structure of the same manufactured material is shown. SiC particles,...mold,...molten metal, 10...stirring bar, 11...melting furnace. Patent applicant Suzuki Automobile Industry Co., Ltd. (and 2 others) Figure 1 Figure 2

Claims (1)

[Claims] Preheated ceramic particles with a particle diameter of 0.1 to 1000 μm and a molten metal of low alloy are placed in a mold and
A method for producing a particle-dispersed composite material, which comprises pressurizing at a pressure of 0,000 kgf/cm^2 to infiltrate molten metal between ceramic particles, immediately remelting it, stirring it, and casting.