JPS61257442A - Manufacture of composite material - Google Patents

Abstract

PURPOSE:To form high quality composite material, by fixing a preformed body made of strengthening material in a mold by exhausting means, and carrying out the sucking operation from feeding of molten matrix metal up to pressing of them, to permeate and fill the molten metal into the formed body. CONSTITUTION:A gas vent 2 is provided at the bottom of the metallic mold 1, and an exhausting path 4 arranged in a knockout 3 is communicated to a vacuum pump 5. The preformed body W made of strengthening material is arranged into contact with the bent 2, exhausted and sucked by the pump 5 to fix the body W in the mold 1. Next, e.g. molten Al M is fed while maintaining the mold 1 to a prescribed temp. then the melt M is permeated into the body W by pressing due to a movable punch 6 and solidified therein. When solidification is completed, operation of the pump 5 is stopped, air is fed in the path 4 and product is taken out by the knockout 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a composite material comprising a reinforced ten-dimensional preformed body and a matrix metal.

(Prior art and its problems) Currently, reinforcement materials made of boron, carbon, alumina, silica, silicon carbide, etc. are infiltrated and solidified with matrix metals such as molten aluminum and magnesium to achieve high strength and high elasticity. Composite materials are in the spotlight.

The method used to manufacture this composite material is a high-pressure casting method in which the molten matrix metal is pressurized at high pressure in a mold and uniformly penetrates into the pre-formed reinforcing material. It is extremely difficult to properly fix it to the surface and form it without leaving any air inside.

Regarding the method of impregnating a reinforcing molded body with molten metal, a method has been proposed in which the internal air of the molded body is degassed and the molten metal is impregnated under reduced pressure to prevent deformation and damage of the molded body (Japanese Patent Laid-Open No. 60-6265).

However, in method 2, the pressure required for the molten metal to penetrate is high for molded bodies made of materials that have poor wettability with the molten metal, or for molded bodies made of materials with small fiber and particle sizes, and under reduced pressure, the molten metal is completely impregnated. The problem is that it is not.

(Summary of the Invention) The present invention provides that in such a high-pressure casting method, if the pre-formed body is fixed by suction under reduced pressure, the pre-formed body does not have to be processed and fixed by fitting into the mold. If the suction operation is continued from the time of supplying hot water to the matrix metal to the time of pressurization, the matrix metal can easily penetrate into the pre-formed body, and residual air can be expelled to form a hollow-free molded body. We found that a high-quality composite material can be formed and completed it, so it is impossible to impregnate the molten metal only by vacuum suction. The purpose of this invention is to provide a method for impregnating molten metal into 2) fibers with small diameters, such as whiskers, and 3) particles with small particle diameters. The gist is a high-pressure composite monthly manufacturing method in which a pre-formed reinforcing material is fixed in a mold, and molten matrix metal supplied into the mold is pressurized by a movable bonder to penetrate into the pre-formed material. The preformed body is placed on the inner wall of the mold or the movable bonder pressurizing surface (J is brought into contact with the exhaust hole of the movable bonder and suctioned), and the suction operation is continued from the supply of hot water to the molten matrix metal and during pressurization. The method of manufacturing a composite molded body is characterized in that the preform is infiltrated and filled with matrix metal while evacuating residual air by reducing the pressure inside the preform.

(Configuration of the present invention) In the present invention, the preformed body contains poron and carbon.

Fibers and thin wire materials such as alumina, phosphoric acid, and silicon carbide.

Reinforcing materials such as powdered materials and whiskers are used.

As the matrix metal, metals such as aluminum or magnesium, which are usually used as fiber-reinforced metal grains, or alloys thereof are used.

The mold used is a mold used for normal high-pressure casting with an exhaust hole for vacuum suction.

Specifically, as shown in Fig. 1, a gas vent (2) is provided at the bottom of the mold (1), and a vacuum pump (5) is provided through an exhaust passage (4) provided in the knockout (3). The pre-molded body (W) is connected to the gas vent (2) and placed in contact with the gas vent (2).
can be fixed in the mold (+) by suctioning it under reduced pressure. Note that (5) is a movable punch for pressurizing the molten metal.

The gas vent (2) for vacuum suction is made of composite material @(
(See Fig. 2 (a) to (f)), it can be installed at the side wall of the mold or at the position of the pressurizing surface of the movable punch.
Considering the work process, it is desirable to arrange it at the bottom of the mold as shown in FIG. 1 and to vacuum suction through the exhaust passage (4) in the knockout (3).

1. The structure of the cass vent (2) prevents molten metal from entering the exhaust passage (4) during the supply and pressurization of the matrix metal inside the mold.
The hole diameter or slit gap should be adjusted so as not to reduce the exhaust capacity, and the hole diameter or slit gap should be adjusted to 0.5 to 0.01 mm, especially 0.
．． 1 to 0.03 mm is preferred.

This is because if it is 0.5 mm or more, the molten metal will enter more often and the exhaust capacity will be reduced, and if it is 0.01 mm or less, the suction capacity will not be practical.

(Example) Silicon carbide whiskers were formed into a pre-molded body with a diameter of 80 mm and a diameter of 30 mm, and preheated to 630 to 660°C.
Gas vent diameter 0.05mm, size 4. It is inserted into the mold shown in FIG. 1 having 5 mmφ and fixed by vacuum suction from the gas vent. While maintaining the mold at 300-450°C, molten aluminum (casting temperature 750-790°C) was supplied, and after 20 seconds from I0 to I00 Kgf/
Pressure is applied at a pressure of 2 cm2 or more to infiltrate into the preformed body and solidify it. After the solidification was completed, the vacuum pump was stopped, air was introduced into the exhaust passage, and the product was taken out by knockout and inspected, but no bubble defects were found.

(Comparative Example) (1) When the molten metal is pressurized under the same conditions as in the example without vacuum suction, the preform moves during pressurization and bubble defects remain inside. Although this defect became smaller as the pressure increased, the bubble defect was not eliminated even at a pressure of ]000 Kgf/cm2.

(2) A silicon carbide whisker molded body with a volume ratio of 15% and a diameter of 80 x 60 mm is preheated to 630 to 660°C, and a gas vent diameter Q of 05 mm and a size of 4. The first having 5 mmφ
Set it in the mold and fix it by suctioning it under reduced pressure from the gas vent. Δl while maintaining the mold temperature at 450-5000C
The molten metal was drained at about 790° C., and the molten metal was solidified while the molded body was vacuum-sucked without applying pressure to the molten metal. After solidification, the cross section of the casting including the center of the molded body was cut and observed, and as a result, no molten metal was impregnated into the molded body.

(Operations and Effects of the Invention) As is clear from the following explanation, according to the present invention, since the pre-formed body is fixed by vacuum suction force, it is easy to cast composite materials in various forms. In addition, since the vacuum suction exhausts the air that permeates from around the pre-formed body after supplying hot water without leaving any residue, air bubble defects that could not be eliminated even with conventional] Since it can be solved by pressure, it is an extremely superior manufacturing method for each composite phase.

It should be noted that although the present invention has been described using a silicon carbide-aluminum composite material as an example, it is not limited to this type of composite material, and can be widely applied to pressure casting methods.

[Brief explanation of drawings]

Figure 1 (J) Schematic diagram showing the casting state of a mold preferred for use in the method of the present invention, Figures 2 (a) and (b). (c), (d), (e), and (f) are It is a vertical cross-sectional view showing the composite form of each reinforcing material. (1) Mold, (2) Gas vent, (3) Knockout, (4) Exhaust passage, (5) Vacuum pump, (
6)...Movable bond.

Claims (1)

[Claims] (1) A high-pressure composite material manufacturing method in which a pre-formed reinforcing material is fixed in a mold, and molten matrix metal supplied into the mold is pressurized with a movable punch to penetrate into the pre-formed material. The body is fixed by suction by bringing it into contact with an exhaust means provided on the inner wall of the mold or the pressurizing surface of the movable punch, and the suction operation is continued from the supply of molten matrix metal to the time of pressurization to reduce the pressure inside the preformed body. A method for producing a composite material, characterized in that it permeates and fills a matrix metal while evacuating residual air.