JPS5967335A - Fiber reinforced composite member and its production - Google Patents

Abstract

PURPOSE:To provide a fiber reinforced composite member which is light in weight and has improved strength by constituting the same of a precipitation hardening type stainless steel fiber molding and an Al alloy matrix which is subjected to an artificial aging treatment after a soln. heat treatment. CONSTITUTION:The abovet-described composite member is adapted to, for example, a connecting rod for an internal combustion engine. More specifically, precipitation hardening type stainless steel fibers (pH steel fibers) are inserted together with a copper brazing material into a heat resistant glass tube, and are held at 1,120 deg.C to melt. The fibers are partially diffusion-bonded to each other by such melting to form a fibrous molding F, whereafter the molding F is quickly cooled and is hardened by a soln. heat treatment. The molding F is disposed in the cavity of dies for forming a rod part in the axial line direction thereof, and with an Al alloy used as a matrix M a connecting rod is cast by a high pressure solidification casting method. At the same time, the matrix M is packed in the rod part 1 with the molding F, whereby the matrix is fiber-reinforced. The connecting rod is heat-treated at 500 deg.C and is then cooled by using hot water kept at >=60 deg.C to solutionize the Al alloy. On the other hand, the pH steel fibers constituting the molding F is subjected to a precipitation hardening treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fiber reinforced composite member and a method for manufacturing the same.

The applicant first forms a fiber molded article by partially diffusion bonding between inorganic fibers such as stainless steel pot fibers using a copper-based brazing filler metal or by firing.
We have proposed a composite member in which IJ Lux light alloy is filled and composited using a high-pressure solidification casting method, and predetermined locations are reinforced with fibers at the same time as the member is cast. According to the high-pressure solidification casting method described in 1), it is possible to sufficiently fill and composite IJ sox into a fiber molded body, and it can be said that it is an effective means for manufacturing this type of fiber reinforced composite member.

The present inventors have conducted various studies regarding the physical properties of the composite member described in 2. As a result, the fibers are heated at high temperatures during brazing and firing, so the fibers themselves are annealed and their strength is reduced. It was found that the strength of composite members tends to decrease, and that it affects the strength of composite members.

In view of the above, the present invention provides a fiber-reinforced composite member whose strength is improved by using precipitation-hardened stainless steel fibers as reinforcing fibers and subjecting the fibers and the member itself to a specific heat treatment. A precipitation-hardened stainless steel fiber molded body that was subjected to solution treatment and precipitation hardening treatment, and an aluminum composite that was filled and composited into the fiber molded body by high-pressure solidification casting method and subjected to artificial aging treatment after solution treatment. It is characterized by being composed of an alloy matrix.

An embodiment in which the present invention is applied to a connecting rod for an internal combustion engine will be described below.

<Example> 1st. FIG. 2 shows a connecting rod using an aluminum alloy as a matrix. Reference numeral 1 denotes a frame portion, and an annular small end portion 2 and a semi-annular thick end half body 3 are integrally provided at both ends of the frame portion. The frame part 1 is fiber-reinforced by precipitation-hardened stainless steel fiber moldings F arranged in the axial direction.

The above connecting rod is manufactured by the method described below.

First, a precipitation-hardened stainless steel fiber (hereinafter referred to as PI
It is called steel fiber. ) is inserted into a heat-resistant glass tube together with a copper-based brazing material, and held at a temperature of 1.12 (lC) for 15 minutes to melt the brazing material, which partially diffuses and bonds the fibers together to form fibers. The body P' is molded, and then the fiber molded body F is cooled at a cooling rate of 10 C/sec.

Above temperature 1,120tl? is the melting point of the copper-based brazing filler metal and the solution temperature of the p II steel fiber, therefore, by cooling from this temperature at the above rate, the fiber molded body F
is subjected to solution treatment and hardened. This fiber molded product F has a bulk density of 2.65 g/cc and has good shape retention.

Next, the fiber molded body F is arranged in the axial direction in the cavity for forming the frame part of the mold, and a connecting rod is simultaneously cast by high-pressure solidification casting using an aluminum alloy (115AC8B material) as the matrix M. Frame part 1
In the step, the fiber molded body F is filled and composited with the matrix M to be reinforced with fibers.

After that, the connecting rod was heated to 500C for 15 hours, then 6
Cool using hot water above 0C. Through this heat treatment, the aluminum alloy serving as the matrix M is subjected to solution treatment, while the PH steel fibers constituting the fiber compact F are subjected to precipitation hardening treatment.

The temperature of the solution treatment and precipitation hardening treatment is 450-510℃.
C is suitable; below 450C, precipitation hardening of the pH steel fibers is impossible, while above 510C there is a risk of reaction between the aluminum alloy and the pH steel fibers.

After the above treatment, the connecting rod is heated to 170C for 110 hours and then air cooled to perform artificial aging treatment on the aluminum alloy as the matrix M, thereby improving the strength of the aluminum alloy.

Figure 3 shows pH steel fiber (I) and JIS SUS 2.
7 shows the elastic proportional limit of stainless steel fiber (TI), where Δ is before heat treatment of each fiber, B is after solution treatment, and C is after precipitation hardening treatment. As is clear from Figure 3, the strength of the PH steel fiber (I) is significantly improved by the heat treatment as compared to the other stainless steel fiber (II).
Due to the strength improvement of this pH steel fiber and the strength improvement due to the solution treatment and artificial aging treatment of the aluminum alloy, the elastic proportional limit of the connecting rod rod part 1 is 7,500 kf/md for the one using PHm fiber, which is higher than that of stainless steel. 5,500 ky/mi using fiber (If)
A dramatic increase was observed compared to .

As described above, according to the present invention, it is possible to provide a fiber-reinforced composite member that is lightweight and has improved strength, and is effective for application to automobile parts such as connecting rods. Furthermore, the combination of the precipitation-hardened stainless steel fiber molded body and the aluminum alloy matrix has the manufacturing advantage that the precipitation hardening treatment of the fiber molded body and the m-body conversion treatment of the matrix can be performed in one step.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a longitudinal sectional front view of a connecting rod, FIG. 2 is a sectional view taken along the line II-■ in FIG. 1, and FIG. 3 is a graph showing changes in the elastic proportional limit. It is. F...Fiber molded body, M...Matrix Fig. 1 Fig. 2

Claims (2)

[Claims] (1) A precipitation-hardened stainless steel fiber molded body that has been subjected to precipitation hardening treatment after solution treatment, and aluminum that has been filled and composited into the fiber molded body by high-pressure solidification casting method and has been subjected to artificial aging treatment after solution treatment.・Fiber-reinforced composite material consisting of ram alloy matrix. (2) A process of forming a fiber molded body at high temperature using precipitation hardened stainless steel fibers, a process of completing a solution treatment for the fiber molded body by cooling the fiber molded body, and A step of filling and compounding an aluminum alloy as a matrix using a high-pressure solidification casting method and simultaneously casting a member, heating and cooling the member to perform a precipitation hardening treatment on the fiber molded body, and at the same time forming the IJ sock solution. A method for manufacturing a fiber-reinforced composite member, comprising the steps of applying a treatment, and heating and cooling the member again to subject the matrix to artificial aging treatment.