JPH04160127A - Manufacture of parts composed of particle dispersed composite material - Google Patents

Abstract

PURPOSE:To obtain a composite material having high density and excellent hardness, wear resistance, heat resistance, strength, fatigue strength and Young's modulus by incorporating ceramic particles into a die, pressurizing to form a preform, pouring molten metal for matrix and immediately pressurizing. CONSTITUTION:The preheated ceramic particles 10 are incorporated into a side die 1 having outer shape of valve retainer, etc., in the inner wall thereof. The particles together with the die are pressurized with an upper punch 3 and a lower punch 2 to form the preform 4. The molten metal 6 of Al alloy or Mg alloy is supplied on the upper part of the preform 4 and immediately pressurized with the upper punch 3. The molten metal is penetrated among the ceramic particles 10 to form the parts composed of particle dispersed composite material. The part composed of only the matrix alloy at the upper part of the obtd. composite part 8 is removed by cutting and a through-hole is finish-worked to complete the valve retainer.

Description

[Detailed Description of the Invention] a. Industrial Application Field The present invention is ^! The present invention relates to a method for manufacturing automobile parts, particularly parts made of composite materials such as valve retainers for engines, in which high-hardness ceramic particles are uniformly dispersed and composited using an alloy or Mg alloy as a matrix.

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

For example, after making a preform using fibers or whiskers such as SiC or C, and setting this in a mold,
This is a method to create a composite material (FRM) by pouring molten metal such as an alloy and impregnating it into a preform 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 mechanically stirred to form a composite material (MMC).

Furthermore, particles such as SiC and C and AI! A widely used method (powder metallurgy method) is to mix powders such as alloys and produce composite materials by hydrostatic compression, hot extrusion, sintering, or the like.

In addition, particles such as 5iC4'C and powders such as ^1 alloy are mixed, and this is mechanically stirred under hot conditions to knead particles such as SiC and C into the alloy powder, resulting in a particle-dispersed composite material. There is a method (mechanical alloying method).

In addition, engine valve retainers, which are automobile parts, are usually made of iron-based materials, such as JIS 520C or JIS
Using 5Cr415 etc., heat treatments such as refining, carburizing and quenching, and tempering are performed.

In addition, various parts are generally manufactured by a die casting method or a molten metal casting method using an AlMg alloy.

C1 Problems to be Solved by the 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 used as particles added to the molten metal, they are uneven (in order to disperse uniformly, the addition ratio to the molten metal is 20-t).
% 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 and therefore expensive, and has the disadvantage that it takes many steps to complete it 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.

On the other hand, when iron parts are used for the valve retainer as described above, it becomes heavy and the generated load (p=-
- Since a) becomes large, there is a problem that it becomes functionally disadvantageous.

In addition, ordinary ^1 alloys and Mg alloys have low mechanical properties such as Young's modulus and hardness, and cannot be applied directly to valve train parts in particular.

The present invention has been made in view of the above-mentioned circumstances, and aims to solve the above-mentioned problems and, in particular, to provide a method for manufacturing parts in which ceramic particles are dispersed and composited.

d. Means for Solving the Problems In accordance with the above object, the present invention provides a mold in which the outer shape of the component is formed on the inner wall, and forms a preformed body by housing and pressurizing ceramic particles in the mold. Then, the above-mentioned problem was solved by pouring the molten metal of ^l or Mg matrix alloy into the preform and applying pressure immediately to infiltrate the molten metal into the preform.

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

FIG. 1 conceptually illustrates the molds used in the present invention, including a horizontal mold L whose inner wall has the external shape of a component to be manufactured, for example, a valve retainer, and a center of the horizontal mold Mg. It is composed of a lower punch 2 fitted to the bottom, and an upper punch 3 located above the lower bunch 2 and fitted into the horizontal mold 1 from above.

The lower punch 2 has a bar portion 2a erected in order to form a central through hole of the valve retainer to be manufactured.

The composite additive material used is SiC+＾j! □0. .

Ceramic particles with high hardness such as Si bulk Na, TiCt WC+Zr0t, etc. are used. The particle size (average particle size) of this ceramic is in the range of 0.01 to 30 microns.

Particles with a particle diameter of less than 0.01 μ are difficult and expensive to manufacture, and are difficult to form into a uniform composite. Furthermore, if the particle size exceeds 30 μm, no improvement in the strength of parts manufactured using the particles can be expected.

Matrix alloys include He-E alloy and Mg alloy such as JIS Near 075. Use MP5 etc.

First, the ceramic particles are preheated at a temperature of 300 to 900° C. in order to remove moisture contained therein and to make it easier for molten alloy to be added later to penetrate. If the preheating temperature is less than 300°C, the molten metal that comes into contact with it will solidify immediately and will not penetrate into the ceramic particles sufficiently.If the preheating temperature exceeds 900°C, it will take time for the molten metal to solidify. Therefore, some components in the ceramic particles (such as free C) and the molten metal ^! etc. react to form a compound (for example, A j! sca)
This is not desirable because it creates

First, the horizontal mold 1 and the lower bunch 2 are heated in advance so that the ceramic particles to be accommodated are not rapidly cooled. After accommodating the ceramic particles 10 in the chamber, as shown in FIG.
Pressure is applied to form a preformed body 4 of ceramic particles.

Here, if the pressure P1 is less than 1 kgf/cj, the strength of the preformed body will not be increased, and it will be deformed or broken in a later process. Furthermore, if the pressure P exceeds 10,000 kgf/c+4, the particle density becomes too high, the molten metal added in a later step becomes difficult to penetrate, and problems arise in the strength of the mold itself.

Next, molten metal 6 made by heating ^1 alloy or h alloy to 660 to 850''C is supplied to the upper part of the preformed body 4 in the horizontal mold 1, as shown in the same figure (C). .

Next, as shown in the same figure, a pressure Pt of 100 to 100,100 O0/d is applied using the upper punch 3. If the pressure P is less than 100 kgf/cj, the gap between the ceramic particles is Penetration of the molten metal is not sufficient, and if it exceeds 100,100 O0/d, problems will arise in the strength of the mold.

In the valve retainer manufactured in this way, the molten metal 6 of the matrix alloy penetrates into the gaps between the layers of ceramic particles forming the preformed body 4, and there, the particle-dispersed composite part 8
is formed, and the upper part is made of a non-composite matrix alloy, which serves as a machining allowance.
is obtained.

The valve retainer as shown in FIG. 2 is completed by cutting away a portion consisting only of the matrix alloy on the upper part of the composite portion 8 and finishing the through hole.

In addition, the part of the matrix alloy that becomes the cutting allowance is the bar part 2a of the lower punch 2 when pressurized by the punch 3.
It is preferable to adjust it so that it is near the tip of the tip to facilitate cutting.

The thus obtained composite portion of the valve retainer contains ceramic particles at a high density of 50 to 90 wt%.

Next, some specific examples will be described.

Specific Example 1 First, SiC with a particle size of 1μ■ is used as the ceramic particles, and it is preheated to soo 'c to 300''
After this was placed in the lower punch 2 and the horizontal mold 1 heated to C, it was pressed with P of 500 kgf/d to obtain a preform.

Next, as a matrix alloy ^! Alloy JIS606
1, heat it to 750"C and melt it to form horizontal mold 1.
100100O/
Pressure was applied from above at a pressure Pt of d. After demolding, finishing was performed to obtain a valve retainer as shown in FIG.

Concrete Example 2 Using ^i tos as the ceramic particles and 1 alloy JISMP5 as the matrix alloy, they were treated under the same conditions as in Concrete Example 1, and A j! A component made of a composite material in which gos was evenly distributed was obtained.

e. Effects of the Invention As described above, parts manufactured by the method of the present invention have particles with a very high density (50 to 90 wt%) compared to when molded using a composite material in which particles are dispersed in advance. It is made of a dispersed composite material, and therefore has excellent hardness, wear resistance, heat resistance, 1 strength, 9 fatigue strength, and Young's modulus, and can be used as a substitute for iron-based parts. Furthermore, when this is applied to a valve retainer, it becomes possible to replace the conventional iron-based valve retainer, contributing to higher engine speeds and lower fuel consumption, and resulting in weight reduction.

Furthermore, since the method of the present invention uses a casting method, the manufacturing cost is low and the number of steps is small.

[Brief explanation of the drawing]

FIGS. 1(a), (b), (C), and (d) are diagrams explaining the procedure for manufacturing a valve retainer using the method according to the present invention, and FIG. 2 is a diagram showing the completed valve retainer.
FIG. 1...Horizontal mold, 2...Lower punch, 3...
- Upper punch, 4... Preformed body, 6... Molten metal, 8... Composite part.

Claims (1)

[Scope of Claims] 1) A mold with the outer shape of the part formed on the inner wall is provided, and ceramic particles are placed in the mold and pressurized to form a preform, and then directly coated with Al or Mg. A method for manufacturing a part made of a particle-dispersed composite material, characterized by pouring a molten metal of a matrix alloy and immediately applying pressure to infiltrate the molten metal into a preform. 2) A horizontal mold in which the outer shape of the valve retainer is formed on the inner wall, and a lower punch having a bar portion that forms the central through hole of the valve retainer erected within this horizontal mold, and After accommodating a predetermined amount of ceramic particles, pressure is applied to form a ceramic preform.Next, while this preform is housed in this horizontal mold, A is placed on the top of the preform.
From the particle-dispersed composite material according to claim 1, characterized in that after pouring a predetermined amount of molten metal of a matrix alloy of Mg or Mg, pressure is immediately applied to infiltrate the molten metal into the preform. How to manufacture parts.