JPS5887238A - Manufacture of fiber reinforced composite member - Google Patents

Abstract

PURPOSE:To manufacture the titled composite member with superir mechanical strength by forming plating layers on the surfaces of innumerable metallic inorg. fibers, partially sintering the layers in a molding tool, filling the resulting molded body into a matrix, and combining them. CONSTITUTION:Plating layers of pure copper or the like are formed on the surfaces of innumerable unidirectional metallic inorg. fibers, and the fibers are put in a heat resistant tubular molding tool such as a quartz glass tube at a prescribed bulk density. The tool is placed in a heating furnace kept in a reducing or inert gaseous atmosphere or a vacuum, and by heating the fibers, together with the tool, to a low temp., the plating layers are partially sintered. The resulting molded body is filled into a matrix and combined by a high pressure solidification casting method.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a fiber-reinforced composite member, in which metallic inorganic fiber molded bodies are filled and composited by IJ Lux medium-high pressure coagulation casting method.

Here, the high-pressure solidification casting method is a special casting method in which a hydrostatic high pressure of 500 to 2,000 kg/d is applied to the molten metal poured into a mold, and the molten metal is solidified under the high pressure. When the molded body is filled and composited into the matrix, it is possible to sufficiently infiltrate the molten metal called IJ lux over the entire area of the molded body, and a composite member with excellent mechanical strength can be obtained.

The present applicant previously made a molded body of Ofl/CC with a bulk density of 2.5 to 5, which is made of highly elastic metallic inorganic fibers and whose fibers are partially diffusion-bonded by a copper-based filter material, to the above-mentioned casting method. We have developed a method for manufacturing a fiber-reinforced composite material in which a matrix is filled and composited using a method (see Japanese Patent Application No. 56-40993). The molded body has good shape retention due to partial diffusion bonding between the fibers using the copper brazing filler metal, and this shape retention is maintained even during casting, so desired parts of the member can be appropriately reinforced with fibers. can do.

However, as a result of various studies regarding the molded article, it has been found that there are the following problems. That is, when forming the compact, the fibers are heated together with the copper-based brazing material to a temperature higher than the melting temperature of the brazing material, for example, about 1,200° C. or higher, and then cooled in a furnace, so that the fibers themselves are not annealed. hand,
It tends to significantly deteriorate its strength. Figure 7 shows two types, namely JIS SUS□33 materials with a diameter of 0.37.
Dragon stainless steel wire (α) and JIS SUS 27
This figure shows the change in breaking strength at room temperature when stainless steel thin wire 1 (HL) with a diameter of 0.37 mm is heated for 15 minutes. This figure also shows that the strength deteriorates significantly when the thin wire is heated to high temperatures. This deterioration tendency also appears in other iron-based thin wires.

In view of the above, the present invention is to prevent strength deterioration of the fibers by forming a molded body without heating the fibers at high temperatures, and to appropriately fiber-reinforce desired parts of a member using the molded body. The purpose of the present invention is to provide a method for manufacturing the above-mentioned composite member, in which a plated layer is formed on the surface of countless metallic inorganic fibers, and the metallic inorganic fibers are partially sintered between the plated layers. The method is characterized in that a molded body made of fibers is molded, and the molded body is filled and composited into a matrix by a high-pressure solidification casting method.

The above-mentioned metallic inorganic fiber has high elasticity,
This includes stainless steel fibers and other iron-based fibers. In addition, the plating layer is formed by copper-based, silver thread electroplating or chemical plating, and the thickness of the plating layer is in the range of 0.1 to 4.0 μm from the viewpoint of fatigue strength of the composite member, as is clear from Figure 6. Optimal.

If the thickness of the plated layer is less than 0.3 μm, the shape retention of the molded product will be poor (and if it exceeds 4.0 μm, the plated layer and matrix layer will react significantly, reducing the fatigue strength of the composite member.

To explain the partial joining process between fibers using a plating layer, for example when obtaining a rod-shaped molded product, first, a plating layer is formed using pure copper on the surface of countless unidirectional metallic inorganic fibers, and the fibers are bonded together. A heat-resistant tubular mold such as a quartz glass tube is molded with a predetermined bulk density, e.g. 2.5~5,09/
QC, then the mold is placed in a heating furnace maintained in a reducing or inert gas atmosphere or vacuum, and then the fibers together with the mold are heated at a low temperature, e.g.
The plated layers are partially sintered by heating to 00 to 600°C.

Hereinafter, an embodiment will be described in which the present invention is applied to manufacturing a connecting rod for an internal combustion engine whose frame portion is reinforced with fibers.

[Example I]

As shown in Fig. 3, a copper plating layer is formed on the surface of stainless steel fibers f having a polygonal cross section with an average diameter of about 30μ, and the fibers are inserted into a mold P made of a quartz glass tube, and then the mold Place P in a heating furnace maintained in a reducing gas (for example, ammonia decomposition gas) atmosphere, and then heat the fiber bundle together with mold P at about 600°C for 15 minutes to sinter the copper plating layers, Cool the rod-shaped compact F in the furnace as it is.
was molded.

When the properties of the molded article F were examined, it was found to have good shape retention and a bulk density of 3.2 g/cc.

Next, the rod-shaped molded body F is installed in the longitudinal direction inside the frame cavity of a mold for a connecting rod of an internal combustion engine, and the matrix M
Using an aluminum alloy (JISAC8B material) as a material, the frame R is formed by high-pressure solidification casting as shown in Figures 1 and 2.
A connecting rod C reinforced with fiber S was cast.

When the frame R of the connecting rod C was crossed and the properties of the cross section were examined using a microscope, the results shown in FIG. 4 were obtained.

The magnification of FIG. 1 is 400 times, and it can be seen that each polygonal stainless steel fiber and matrix are tightly bonded, the filling composite property is good, and there is no reaction between the copper and aluminum alloy. In Figure 5, the thickness of the plating layer is 5 μm.
It was found that the copper and aluminum alloy reacted significantly as shown in the black part, and the fatigue strength decreased and the durability of the connecting rod was poor.

[Example ■]

A silver plating layer was formed on the surface of polygonal cross-sectional stainless steel fibers with an average diameter of about 30 μm as in Example ①, the fiber bundle was inserted into a mold made of a quartz glass tube, and the mold was then placed in a reducible mold. The fiber bundle is placed in a heating furnace maintained in a gas (for example, ammonia decomposition gas) atmosphere, and then the fiber bundle together with the mold is heated at approximately 560°C for 15 fi to sinter the silver plating layers, and then cooled in the furnace. A rod-shaped compact was molded.

When the properties of the above-mentioned molded article were examined, it was found that the shape retention was good and the bulk density was 3.4 gAC-.

Next, the rod-shaped molded body was placed in the longitudinal direction inside the frame cavity of a mold for a connecting rod of an internal combustion engine, and a connecting rod with a fiber-reinforced frame was cast using an aluminum alloy (JIS, ACBE material) by high-pressure solidification casting.

When the frame of the connecting rod was crossed and the properties of the cross section were examined using a microscope, it was found that the polygonal stainless steel fibers and the matrix were tightly bonded, as in Example T, and the filling composite properties were good. It was observed that there was no reaction between the aluminum alloy and the aluminum alloy.

As described above, according to the present invention, a molded body made of the metallic inorganic fibers is formed by forming a plating layer on the surface of countless metallic inorganic fibers and partially sintering between the plated layers. Therefore, sintering between the plated layers can be performed at a relatively low temperature, and deterioration in the strength of the fiber can be prevented.

In addition, the shape retention of the molded body is good, and the shape retention is maintained even during high-pressure solidification casting, so desired parts of the component can be appropriately reinforced with fibers, and fiber reinforced with excellent mechanical strength. A single composite member can be provided.

[Brief explanation of the drawing]

Figure 1.2 shows a connecting rod for an internal combustion engine obtained according to the present invention. Figure 1 is a vertical front view, Figure 2 is a sectional view taken along the line ■-■ in Figure 1, and Figure 3 is a metallic connecting rod. A perspective view showing a part of the molding process of an inorganic fiber molded article, FIG. 4 is a microscopic photograph of a cross section of a conrod rod for an internal combustion engine, FIG. 5 is a microscopic photograph similar to FIG. 4 of a comparative example, FIG. 6 is a graph showing the relationship between the plating layer thickness of metallic inorganic fibers and the fatigue strength of a composite member, and FIG. 7 is a graph showing the relationship between the heating temperature of a thin stainless steel wire and the room temperature breaking strength of the thin wire. f... Stainless fiber, F... Molded body, M... Matrix Patent applicant Honda Motor Co., Ltd. Figure 2 C / Figure 3 Figure 1? Figure 6E Figure 7

Claims (1)

[Claims] A plated layer is formed on the surface of countless metallic inorganic fibers, and a molded body made of the metallic inorganic fiber is formed by partially sintering between the plated layers, and the molded body is formed by high-pressure solidification casting. A method for producing a fiber-reinforced composite member, which comprises filling and compounding the material in a matrix.