JPS6310059A - Manufacture of fiber reinforced metal composition material - Google Patents

Abstract

PURPOSE:To obtain the fiber reinforced metal composite material of excellent mechanical property by charging a preform of a fiber like substance having a higher melting point than that of a matrix metal into a die and partially pressing the composite body formed by impregnating a molten metal into the preform with its pressing. CONSTITUTION:The molten metal 4 of an Al alloy is poured into the molten metal container part of the lower die platen immediately after charging the preform 1 of a silicon carbide whisker into a mold 2 with its preheating. The molten metal 4 is pressed by the plunger 7 having a double action mechanism and impregnated into the whisker preform 1. The Al alloy molten metal is impregnated and filled into the whisker preform 1 and at the time of the pouring reaching the limit further pressing is performed by the inner side plunger 8 of the double action plunger 7 and it is held until the solidification of the whole composite materials is completed.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is directed to chopping continuous fibers such as oxide, carbide, and nitride ceramics whiskers or carbon tA fibers, silicon carbide fibers, and alumina fibers into short pieces. The present invention relates to a metal-based composite material reinforced with short fibers, particularly a method for producing the composite material by high-pressure molten metal impregnation.

[Conventional technology]

If short fibers with excellent heat resistance, tensile strength, and modulus of elasticity, such as whiskers of C. setunthus and various types of ceramic-based twisted fibers, are combined with each filler metal W4, properties such as tensile strength and modulus of elasticity will be excellent. It is known that composite materials can be obtained.

An example of a conventional method for manufacturing such a composite material will be explained with reference to FIGS. 4 and 5.

First, short fibers such as whiskers are mixed with water, an organic resin solution, or an aqueous solution to which inorganic salts are added to form a slurry, and this is filled and compressed into a mold or the like to form a preform. This preform is then preheated and placed in a mold as shown in FIG. In FIG. 4, 1 is a preform, 2 is a mold, 3 is an upper mold platen, and 5 is a lower mold platen. Next, as shown in FIG. 5, after pouring the molten metal 4 into the molten metal container of the lower mold platen 5, the pressurized plunger 6 impregnates the short fiber preform 1 with the molten metal GJ4 to form a composite material. obtain.

An example of the conditions for producing a composite material combining silicon carbide whiskers and aluminum alloy by this method is as follows: preform preheating temperature 650°C, aluminum alloy molten metal temperature 75 otl, molten metal pressing force 800 kl/cm.
It is possible to manufacture composite materials with a content volume ratio of up to about 50.Composite materials may be used in their current state, but they can also be processed by hot extrusion, forging,
After undergoing edge processing such as compression, it is often used to make shapes, carved products, plates, rods, etc.

[Problems to be solved by the invention] Although the above-described method results in a generally satisfactory composite of short fibers and metal, fine porosity often remains inside the composite material, especially in the center. . In ordinary metal materials, porosity that occurs in cast ingots is almost always eliminated by subsequent plastic working such as rolling and extrusion. However, in the case of the composite material in question, it contains a considerable amount of short fibers, so the porosity is crushed by plastic processing and appears to disappear, but it is not completely crimped and bonded. This decreases the mechanical properties of the material and is a major cause of poor reliability of the composite material. In particular, the negative impact on fatigue strength is significant, and in order to put composite materials into practical use over a wide range of areas, there is a strong need to develop a manufacturing method for composite materials due to the generation of microporosity.

It is an object of the present invention to provide a method for producing a covering material that meets the needs of tobacco smokers.

[Means for solving the problems] The present invention provides the following features in the production of a total 4-matrix composite material:
If the melting point is higher than the melting point of the matrix metal, a preform of a conical material with a sublimation temperature is placed in a mold, and the molten metal is pressurized to impregnate the preform, and impregnation is achieved. This method of manufacturing a fiber-reinforced metal composite material is characterized in that the formed composite is further partially pressurized at the point of death.

In the above structure of the present invention, it is preferable to provide a heat insulating layer in advance in the part to be partially pressurized so as to delay the completion of solidification in the vicinity thereof.

The causes of microporosity include micro-shrinkage during solidification of nine metal molten metal by high-pressure impregnation into the preform, which is a high-density aggregate of short am, and replenishment of the molten metal through a high-density aggregate of fibers. It is thought that this remains as a result of insufficient performance. Therefore, in the present invention, the liquid phase of the metal permeates into the shrinkage by partially pressurizing the bath water at an intermediate point between the start of solidification and the completion of solidification after high-pressure impregnation), thereby causing the metal liquid phase to permeate into the shrinkage and disappear.

[Effect]

As mentioned above, since pressurization is applied before the solidification is completed and the liquid phase remains partially, the city easily disappears during shrinkage.

A fruit of this invention! ! The embodiment will be explained with reference to FIGS. 1 and 2. :' In figures a1 and f￥2, the same symbol F as in figures 4 and 5! The same part as FIGS. 4 and 5 is shown. 7
is a double-acting granger, and 8 is its inner plunger.

Pour molten metal 4 of 7501: 70751 alloy into the molten lead container of the ten, pressurize the molten metal 4 with a plunger 7 having a compound mechanism (700 kg/α8), and impregnate it into the whisker preform 1. I let it happen.

When the molten alloy 4 impregnates and fills the whisker preform 1 and the injection reaches its limit, the inner plunger 8 of the double-acting plunger 7 is used to pressurize (Surface pressure on the top surface of the plunger (so o o k2/
eWl”) L, held until solidification of the entire composite material was completed.

The axial cross section of the nine composite materials manufactured by this method was polished and finished with an acid solution (@Nitrica10Q Q: /4, chromic acid sat/t).
s Hydrofluoric acid 1o a: / L b remaining water) K 'C
After etching, fluorescent penetrant inspection was performed, but no defects were detected.

On the other hand, in the above inspection of composite materials manufactured by the conventional method that does not perform two-stage pressurization with a double-acting plunger,
Microgastric porosity was detected on the lower side (plunger side) of the central part of the cross section.

) Inside the double-acting plunger of the present invention, place a cloth or fabric made of fiber or silicon carbide fiber, etc. By coating the plunger with Tux to provide a heat insulating effect; by partially retarding the solidification of the upper part of the plunger and pressurizing it, the effect of eliminating defects could be greatly improved.

The composite material obtained by the method of the present invention retains the effects of the present invention even after post-processing such as hot extrusion without losing the effects of the present invention. That is, the fatigue strength of an extruded material (e1a whisker/7075 μm composite material extruded material, whisker content volume ''X30%) obtained by hot extruding (extrusion ratio 10:1) the composite material produced by the method of the present invention as a billet is A comparison of the fatigue strength of a homogeneous composite material produced by the conventional method with a hot extruded material under the same conditions resulted in the results shown in Figure 5, indicating that the composite material produced by the method of the present invention has superior effects. It became clear that

Furthermore, Figure 3 is a chart showing the number of repetitions until breakage and the N coefficient of stress. The physical properties of the hot extruded material are shown below.

FIG. 9 is a diagram for explaining the method for manufacturing the composite material, showing that the obtained 9ff1J1 reinforced composite material has excellent effects even in subsequent mechanical processing.

Claims (1)

[Claims] In the production of metal matrix composite materials, a preform of a fibrous material with a melting point or sublimation temperature higher than the melting point of the matrix metal is charged into a mold, and molten metal is pressurized to impregnate the preform. A method for producing a fiber-reinforced metal composite material, which comprises further partially pressurizing the formed composite when the above is achieved.