JPH03146253A - Production of metal base composite material - Google Patents

Abstract

PURPOSE:To efficiently produce the metal base composite material having high strength by putting a reinforcing material preformed body to place except center part of a metallic mold at the time of press pouring molten base metal under putting the preformed body composed of reinforcing material in the metallic mold. CONSTITUTION:The metallic mold 10 is constituted of two pieces of thick plates 10a, 10b, and two preformed bodies 15 composed of the reinforcing material (ceramic whisker, etc.) are preset as mutually facing into cavity 11. The valve 14 is arranged to a gas venting hole 13 in this metallic mold 10 and a flowing- through member 18 is connected with an introducing part 12. In this constitution, by adjusting a valve 14, inner part in the metallic mold 10 is evacuated to vacuum and Al alloy is pressed into the metallic mold 10 from an inserting part 17 in the flowing through member 18 at about 30mm/sec supplying velocity at about 800 deg.C supplying temp. and held at about 10kg/mm<2> pressure for about one min. By this method, the metal base composite material having high density without casting hole 19 is efficiently obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a metal matrix composite material using a high-pressure solidification casting method.

[Prior Art and its Problems] Conventionally, a high-pressure solidification casting method (squeeze casting method) has been used as a method for manufacturing metal matrix composite materials. In this method, a preformed body made of reinforcing material such as ceramic whiskers is placed in the cavity of a casting mold, and then
Molten base metal is press-fitted into a preform and cast. The metal matrix composite obtained by this method has mechanical properties such as high strength and excellent wear resistance.

However, when a molten base metal, particularly aluminum or an aluminum alloy, is supplied to a cavity, press-fitted into a preform, and cast, a blowhole is generated in the center of the cavity. The metal matrix composite material in which these cavities exist is
Mechanical strength such as bending strength is poor. Therefore, it is necessary to prevent the formation of blowholes in the metal matrix composite material obtained.

Further, in the conventional high-pressure solidification casting method, the air contained in the preform cannot be sufficiently degassed, and therefore a high-density metal matrix composite cannot be obtained. For this reason, it is not possible to manufacture a high-strength metal matrix composite material.

The present invention has been made in view of this point, and an object of the present invention is to provide a method for manufacturing a metal matrix composite material that can efficiently obtain a high strength metal matrix composite material.

[Means for Solving the Problems] The present invention provides a metal matrix composite using a high-pressure solidification casting method in which molten base metal is press-fitted into a preformed body made of a reinforcing material placed in a mold. In the method for manufacturing the reinforcing material, the reinforcing material preform is placed in a place other than the central part of the mold and then vacuum degassed.

Here, it is preferable to evacuate the inside of the mold immediately before press-fitting the molten base metal. Moreover, it is particularly preferable to arrange two preforms in a mold so as to face each other, and to supply the base metal into the gap between them.

[Function] According to the method for manufacturing a metal matrix composite material of the present invention, the preform is placed in a part of the mold where blowholes occur, that is, in a part other than the central part, and high-pressure solidification casting is performed. , manufacturing metal matrix composites.

Since blowholes occur in the center of the mold, it is possible to prevent blowholes from forming inside the preform.

In addition, by evacuating the inside of the mold immediately before press-fitting the molten base metal into the preform, the air inside the preform can be sufficiently released.

Therefore, the base metal in a molten state can be sufficiently impregnated into the preform, and a high-density metal matrix composite can be obtained.

Therefore, it is possible to obtain a high-strength metal matrix composite material free of blowholes and associated defects.

Furthermore, according to the method for manufacturing a metal matrix composite material of the present invention, by placing a plurality of preforms in an area other than the center part of the mold, the center part where blowholes occur can be used as a product part. A plurality of metal matrix composites can be manufactured using one mold without using the metal matrix composite.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

Example 1 FIG. 1 is an explanatory diagram showing a part of the apparatus used in the method for manufacturing a metal matrix composite material of the present invention.

In the figure, 10 is a mold. The mold 10 has two thick plates 10a,
10b, and when the two thick plates are put together, they form a cavity 11, an introduction part 12 for supplying the molten base metal, and an exhaust port 13 for exhausting the air inside the mold. There is. A valve 14 is attached to the exhaust port 13 to regulate the exhaust inside the mold. Two preformed bodies 15 made of reinforcing material such as ceramic whiskers are placed in advance in the cavity 11 facing each other.

Further, the bottom of the mold 10 is connected to a flow member 18 having an opening 16 at one end so as to communicate with the introduction section 12 and an insertion section 17 at the other end into which a plunger (not shown) is inserted. There is.

Using this device, the dimensions are 120m+mX as follows.
A metal matrix composite material having a size of 120 mm and a thickness of 25 mm was manufactured.

Here, SiC whiskers were used in the preform, and the content thereof was 20% by volume based on the product. Furthermore, aluminum alloy AC8A was used as the base metal.

First, two SiC whisker preforms were placed in the mold 1. Next, before press-fitting the aluminum alloy into the mold 1, the valve 14 was adjusted to evacuate the inside of the mold 10 to a vacuum. Finally, the aluminum alloy was introduced into the mold 1 at a feed rate of 30 yam/see and a feed rate of 800° C. to impregnate the preform.

At this time, the preformed body was also heated to 800°C in advance.

Thereafter, the pressurized state was maintained at a pressure of 10 kg/Ryu 2 for 1 minute, and then the cast body was taken out from the mold.

Two metal matrix composites were manufactured by cutting a portion consisting only of the aluminum alloy including the blowhole 19. A blowhole 19 was generated in the center of the mold 10.

The bending strength, presence or absence of blowholes, and presence or absence of pores of the obtained metal matrix composite were examined. The results are shown in Table 1 below. Note that the bending strength was measured by a three-point bending test.

Example 2 A metal matrix composite material was produced in the same manner as in Example 1, except that the inside of the mold was not evacuated.

The bending strength, presence or absence of blowholes, and presence or absence of pores of the obtained metal matrix composite material were examined in the same manner as in Example 1.

The results are also listed in Table 1 below.

Comparative Example FIG. 2 is an explanatory diagram showing a part of an apparatus used in a conventional method for manufacturing a metal matrix composite material. In the figure, 20 is a mold. The mold 20 forms a cavity 21 and an introduction part 22 for supplying molten base metal. Cavity 21
A preformed body 23 made of reinforcing material is placed in advance. The bottom of the mold 20 also has a flow passage member 2 which has an opening 24 at one end so as to communicate with the introduction part 22 and an insertion part 25 into which a plunger (not shown) is inserted at the other end.
It is connected to 6.

Using this device, the size is 120+nX as follows.
A 120 mmq 25+ am metal matrix composite was produced.

Note that the same preform and base metal as in Example 1 were used.

First, a SiC whisker preform was placed in a mold 20. At this time, the preform 23 occupied half of the cavity 21. Thereafter, a metal matrix composite material was manufactured in the same manner as in Example 1. A blowhole 27 was generated in the center of the mold 20.

The bending strength, presence or absence of blowholes, and presence or absence of pores of the obtained metal matrix composite material were examined in the same manner as in Example 1.

The results are also listed in Table 1 below.

Table 1 Reference example: Base material only (non-composite material) As is clear from Table 1, the metal matrix composite material (Example 1.2) produced by the method of the present invention has no cast cavities or voids. The bending strength was excellent with no <10. On the other hand, the metal matrix composite material (comparative example) manufactured by the conventional method had cavities and voids, and its bending strength was inferior to that of non-composite materials.

[Effects of the Invention] As explained above, the method for producing a metal matrix composite material of the present invention can efficiently obtain a high strength metal matrix composite material.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a part of the apparatus used in the method for manufacturing a metal matrix composite material of the present invention, and FIG. 2 is an explanatory diagram showing a part of the apparatus used in the conventional method for manufacturing a metal matrix composite material. FIG. 10.20...Mold, 11.21...Cavity 12.22...Introduction part, 13...Exhaust port, 14...
・Valve, 15.23... Preformed body, 16.24...
・Opening part, 17.25... Insertion part, 18.26...
Flowing member, 19.27...Blow hole. 7 Figure 11

Claims (2)

[Claims] (1) In a method for manufacturing a metal matrix composite material using a high-pressure solidification casting method in which molten base metal is press-fitted and cast into a preform made of reinforcing material placed in a mold, A method for manufacturing a metal matrix composite material, comprising placing the reinforcing material preform at a location other than the central portion. (2) The method for manufacturing a metal matrix composite material according to claim 1, wherein the inside of the mold is vacuum degassed immediately before press-fitting the molten base metal.