JPH0441065A - Manufacturing method of metal matrix composite material - Google Patents

Abstract

PURPOSE:To press-fit a molten metal into a preform having an intricate shape without closing the runner and without shortening the life of a metallic mold and to obtain the metal-based composite material having desired performance down to the terminal parts of the product by individually cooling the terminal parts of the preform by locally cooling members. CONSTITUTION:The molten metal in a cylinder 11a is pressurized by a pressurizing device 12 and the solidification by pressurization is started when the molten metal is filled in the metallic mold 10. A prescribed volume of cooling water is supplied to the respective locally cooling members 15 and the effect of the members 15 as chillers is exhibited when this pressurizing force exceeds a prescribed value. The terminal parts of the preform 20 are thereby respectively spot cooled. The spot cooling by the locally cooling members 15 is continued until the molten metal press-fitted into the preform solidifies completely. The solidification having the directivity heading from the terminal parts toward the body part is progressed in the preform 20 in this way and the aluminum- based composite product uniform over the entire part is 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] A high-pressure solidification method (squeeze cast method) is a method for manufacturing metal matrix composites. The squeeze cast method is a technology in which ceramic whiskers, etc., are pre-formed as a reinforcing material into a shape close to the product, and this molded body is impregnated with metal, and is a technology that can efficiently obtain near-net products of metal matrix composites. It is attracting attention as

By the way, in the squeeze casting method, when the shape of the product becomes complex, the molten metal may completely solidify in the middle of the process.1. The water duct is blocked,
The pressure of the molten metal may not be transmitted to the end, and a product with desired performance may not be obtained. Such a clogging phenomenon can be solved only by improving the runner arrangement 31, but becomes a problem when manufacturing a metal matrix composite product with a complex shape.

Therefore, as shown in FIG. 5, a water passage 3 is installed inside the mold 2.
is provided to actively water-cool the branch portion 5 of the preform from the tip side to prevent blockage of the runner.

[Problems to be Solved by the Invention] However, in the conventional method, since cooling from the tip side of the branch portion 5 is insufficient, the base of the branch portion 5 solidifies faster than the root 6 or the tip side. For this reason, the runner is blocked before the entire branch part 5 is completely solidified, and the pressure of the molten metal is no longer transmitted to the tip side of the branch part 5 during press-fitting, resulting in a defective product. This is because the water cooling effect by the water passage 3 is insufficient and the temperature gradient from the branch section 5 toward the main body section 4 becomes gentle.

Incidentally, in order to improve the cooling effect, it is possible to increase the temperature gradient, but this causes the disadvantage that large stress is generated inside the mold due to thermal strain, and the life of the mold is significantly shortened.

This invention has been made in view of the above circumstances, and allows molten metal to be press-fitted into a complex-shaped preform without clogging the runners or shortening the life of the mold, thereby improving the quality of the product. It is an object of the present invention to provide a method for manufacturing a metal matrix composite material having desired performance up to the end portion.

[Means for Solving the Problems] The method for manufacturing a metal matrix composite according to the present invention includes attaching a local cooling member made of a material having higher thermal conductivity than the constituent members of the mold to the mold, and The preform is placed in a mold so that the end portion of the mold that is difficult for the molten metal to reach directly or indirectly contacts the local cooling member, and the molten metal is supplied to the preform in the mold to cool the local cooling member. It is characterized in that the end portions of the preform are individually cooled by the members.

In this case, it is preferable that the preform is not cooled by the local cooling member at the beginning of the supply of the molten metal, and the end portions of the preform are individually cooled by the local cooling member at the end of the supply.

[Function] In the method for manufacturing a metal matrix composite according to the present invention, the end portions of the preform are individually cooled locally by the local cooling member, so that solidification progresses from the end of the preform toward the main body. It has directivity.

Therefore, the pressure of the molten metal is transmitted to the end portion without clogging a part of the molten metal supply path during press-fitting, and solidification is completed.

In addition, since the end of the preform is actively locally cooled,
Swirl flow inside the cavity is improved. Therefore, the cycle time of casting is significantly shortened, and the progress of solidification can be promoted without hindering productivity.

E. Embodiment Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 and FIG. 2 are schematic diagrams showing a squeeze cast device and a part thereof, respectively, used in a method for producing a metal matrix composite material according to an embodiment of the present invention. here,
A case will be described in which a golf club head made of an aluminum matrix composite is manufactured.

SiC whiskers are mixed with a binder agent having a predetermined component, and this is preformed into the shape of a 5-iron club head to form a preformed body 20. A plurality of club heads 20a are formed in the preformed body 20 so as to branch. The SiC whiskers of the preformed body 20 serve as a reinforcing material, and are made to have a density such that the ratio of the aluminum alloy after gold subsidence is 13% by volume.

In the squeeze casting device, a cylinder 11a communicates with a cavity of a mold 10 via a molten metal passage 13. Inside the cylinder lla, a molten aluminum alloy 14 is housed in a heated state to a predetermined temperature range.

Piston 11. The rod b is connected to the drive shaft of the pressurizing device 12, and the molten metal 14 is pushed by the piston 11b into the mold 1.
It is designed to be press-fitted into the cavity of 0.

A preformed body 20 is charged into the cavity of the mold 10. The preformed body 20 is preheated to a predetermined temperature. The mold 10 is divided in order to take the preform 20 in and out of the mold 10.

As shown in FIG. 1, a plurality of local cooling parts $, T1.5 are embedded in the mold 10. The local cooling member 15 is made of a cylindrical body made of copper alloy, and is assembled so that its tips are in direct contact with the club head 20a of the preformed body. That is, as shown in FIGS. 3 and M4, the tip of the local cooling member 15 is in contact with the ace surface 21 of the club head 20a. The reason why the member 15 is brought into contact with the face surface 21 is that shrinkage holes are likely to occur near the face surface 21.

A water passage is formed in each local cooling member 15, and these water passages communicate with each other inside the mold 10. Further, the water passage communicates via piping 16 with a cooling control device 17 having a cooling water supply source.

The cooling control device 17 includes a flow control valve (not shown) configured to be computer-controlled. A pressure sensor (not shown) of the pressurizing device 12 is connected to the input portion of this flow rate control valve.

Next, a case will be described in which a metal matrix composite product is manufactured by press-fitting a molten metal into a preform using the above-mentioned apparatus.

First, the pressurizing device 12 applies the molten metal 14 at a predetermined pressure to the mold 1.
0 cavity. The molten metal 14 is press-fitted into the preform 20 through the passage 13 and begins to solidify from the outer periphery and ends. When the mold is filled with molten metal, the pressurizing device 12
As a result, the molten metal in the cylinder 1 core a is pressurized and solidification under pressure is started. This pressurizing force is detected by the pressure sensor of the pressurizing device 12, and when this exceeds a predetermined value, a detection signal is input to the input section of the flow rate control valve of the cooling control device 17.

Based on this, a predetermined amount of cooling water is supplied to each local cooling member 15, so that the member 15 functions as a chiller, and the end portions of the preformed body 20 are spot cooled. Spot cooling by the local cooling member 15 is continued until the molten metal press-fitted into the preform is completely solidified. This results in
Directional solidification proceeds inside the preform 20 from the end toward the main body, resulting in an overall uniform aluminum matrix composite product.

According to the above-described embodiment, the spot cooling of the end portion or the flow of the molten metal inside the mold is improved, so that the molten metal can be continued to be pressed into the preform until the end without clogging during casting. For this reason, products manufactured by the conventional method had cavities in the center of the club, but this was eliminated in the above embodiment.

In addition, with conventional products, the tensile strength of the center of the club (a tensile test piece was taken from the center) or 35
The strength was approximately 45 kgf/aII12 in the above example.

[Effects of the Invention] According to the present invention, molten metal is press-fitted into a preformed body having a complex shape, without causing blockage of the runners in the mold, and without shortening the life of the mold. It is possible to obtain a metal matrix composite material having desired performance up to 10%.

Furthermore, since the end portion of the preform is actively cooled, the flow of the molten metal is improved, the casting cycle time is significantly shortened, and productivity can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a part of the squeeze cast device used in the method for manufacturing a metal matrix composite material according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing the entire squeeze cast device, and FIG. 3 is a schematic diagram showing the entire squeeze cast device. 4 are diagrams showing the positional relationship between the local cooling member and the preform, respectively, and FIG. 5 is a schematic diagram showing a part of a squeeze cast device used in the conventional manufacturing method. DESCRIPTION OF SYMBOLS 10... Mold, 12... Pressure device, 14... Molten metal, 15... Local cooling member, 17... Cooling control device, 2
0... Preformed body

Claims (2)

[Claims] (1) A local cooling member made of a material with higher thermal conductivity than the mold component is attached to the mold, and the end portion of the preform that is difficult for the molten metal to reach comes into direct or indirect contact with the local cooling member. A metal characterized in that the preform is charged into a mold so that the preform is placed in the mold, the molten metal is supplied to the preform in the mold, and the end portions of the preform are individually cooled by the local cooling member. Method of manufacturing base composite material. (2) The preform is not cooled by the local cooling member at the beginning of supply of the molten metal, and the end portions of the preform are individually cooled by the local cooling member at the end of the supply. A method for producing a metal matrix composite.