JPS62161460A - Production of preform to produce composite metallic material - Google Patents

Abstract

PURPOSE:To obtain a preform from which a product having decreased variance in product strength, particularly strength by the parts of the same material is obtainable by oscillating a solvent dispersed therein with a reinforcing material while stirring the solvent to defoam the same, then dehydrating and molding the material. CONSTITUTION:A mixture composed of the solvent A such as sq. soln. prepd. by dissolving colloidal silica or PVA in water at about 2-3% concn. and the reinforcing material B dispersed therein is put into a container X. While the content is stirred by a stirrer S, the content is oscillated by using two units of ultrasonic oscillators 1. The foam sticking to the material B is stripped, gathered and floated by oscillating the solvent A and the material B in the above-mentioned manner, by which the solvent and reinforcing material are defoamed. The pressure in the containers X is reduced to accelerate the defoaming at need. The content in the container X is dehydrated under pressurization by using, for example, a filter press Y extended with a net N in the bottom of a pipe P upon ending of stirring and oscillating. Such content is molded and is dried after molding, by which the preform is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a method for producing a preform for producing a metal matrix composite.

[Prior art 1 The metal matrix composite material 11 is made by dispersing reinforcing materials such as ceramics, metal particles, whiskers, short fibers, etc. in a base material of AU, Ma, and Fa gold alloys, and is lightweight yet highly durable. Strength,
In recent years, it has attracted attention as a material with high rigidity or high wear resistance.

One of the most typical manufacturing methods for this metal matrix composite material is to form the reinforcing material into a predetermined shape to form a preform, and then impregnate the preform with molten metal, which is the base material, by applying a predetermined pressure. There is a molten metal forging method.

In the molten metal forging method, reinforcing materials such as whiskers are mixed and dispersed in water or an aqueous solution such as colloidal silica, and this is filtered and pressed or vacuum formed to obtain a preformed body into a predetermined shape. Next, this preform is placed in a mold, a molten base metal is charged from the mold, and the mold is pressed from above to impregnate the molten metal into the preform to produce a product.

[Problems with the Prior Art] However, in the case of the above-described conventional method for manufacturing metal matrix composite materials using the molten metal forging method, there is a drawback that the strength of the product varies, particularly the strength varies depending on the parts of the same material.

The reason for this strength imbalance 4 is that air bubbles attached to the reinforcing material such as whiskers during the preparation of the preform interfere with the uniform distribution of the reinforcement H, and the preform itself is not uniform. It can be raised. Second, when pressurizing with the ram R during melting forging, there is no place for air bubbles to escape, and the preform cannot be sufficiently degassed, which remains in the product as pores.

[Summary of the Invention] The present invention has been made in order to improve the drawbacks of the conventional method described above. In particular, it is possible to effectively remove air bubbles such as whiskers that form in reinforcing materials during the production of preforms, thereby producing a homogeneous preform. It is an object of the present invention to provide a method for producing molded bodies.

For this purpose, the present invention is characterized by dispersing reinforcing material in a solvent when forming a preform, stirring and vibration to remove air bubbles, and then dewatering and forming.b It is.

As the solvent, water or an aqueous solution prepared by dissolving colloidal silica, polyvinyl alcohol, etc. in water at a concentration α of 2 to 3% can be used. Further, a surfactant may be added to this as necessary.

A reinforcing material is dispersed in this solvent, and any commonly used materials can be used as the reinforcing material, such as short metal strings, ceramic rice 7J such as SiC, Si3N4°△△203, etc. 5. Examples include u fibers.

Once the reinforcing material is added to the solvent, it is stirred and shaken. Figure 1 shows an example of this, in which reinforcing material B is dispersed in solvent A in a container
While stirring, the solvent was vibrated with reinforcement 44B at 501.11 to 500 days l using the ultrasonic oscillator 1 at the second base.

By imparting an image to the solvent A and the reinforcing material B in this manner, the air bubbles attached to the reinforcing material B can be separated and defoamed by floating them together.

In the example shown in the figure, the pressure of the container X is reduced to 5 torr or less,
Efforts are being made to promote defoaming. After stirring and shaking, the second
Dehydrate and mold as shown in the figure. In this example, pressurized dehydration and molding are performed using a filtration press device Y in which a net N is stretched on the bottom of the vibrator P. After the finished product is shaped, it is dried and completed γ(5).

The preformed product obtained in this way has a homogeneous shape in which the reinforcing material is evenly dispersed since most of the air bubbles adhering to the reinforcing material have been removed. Therefore, the metal matrix composite material manufactured based on this material is also a product with uniform strength and no variation.

[Example] Using SiC whiskers as a reinforcing material, the preform was made to vJ
Built. SiC whiskers and water were mixed at a weight ratio of 32:100, and the mixture was heated to 100% while stirring under a reduced pressure of 1 torr.
H2, vibration was applied at an amplitude of 1M. The apparatus shown in FIG. 1 was used.

Next, press molding was performed using an over-pressing apparatus shown in FIG. 2 so that the reinforcing material volume fraction Vf was 20% to obtain a preformed body.

A 6061A 1 matrix composite material was manufactured by a molten metal forging method using the preformed body thus manufactured and a preformed body produced by a conventional method without vibration. The number of samples was N=20 for each.

Molten metal forging was performed under the following conditions.

800° C. during production of preform 6061 A temperature: 800° C. Pressing time: 3 minutes Pressing force: IHg/7 resistance 2 After cooling, the obtained product was subjected to T6 treatment and a tensile strength test was conducted. Figure 3 shows the results.

It can be seen that when the preform according to the invention is used, the strength is increased and, in particular, the variation is reduced. .

[Effects of the Invention] As explained above, according to the method of the present invention, a homogeneous preform in which the reinforcing material is uniformly dispersed can be manufactured. Using this preform, it is possible to obtain a platform for manufacturing the gold B3'A composite material, and a product with high strength and little variation.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of an example of the stirring and vibration process in J3 according to the method of the present invention, Fig. 2 is an explanatory diagram of an example of a filtration breather culm, and Fig. 3 is a graph without showing the results of the example. .

Claims (1)

[Claims] 1. A method for producing a preform for producing a metal matrix composite material, which comprises dispersing a reinforcing material in a solvent, stirring and vibration to remove air bubbles, followed by dehydration and molding.