JPS62124245A - Fiber-reinforced metal and its production - Google Patents

Abstract

PURPOSE:To disperse fiber into base material and to improve strength by cooling Al molten alloy containing fiber of silicon carbide, etc., and prescribed percentage of Ni and Mn from a prescribed direction so as to alloy a needlelike phase to crystallize out in the direction perpendicular to the direction of the length of fiber. CONSTITUTION:A molten metal in which one or more kinds among respective continuous fibers of silicon carbide, alumina, and carbon are incorporated in an Al alloy containing 0.5-6wt% Ni and 0.1-2wt% Mn is prepared. This molten metal is solidified by means of high-pressure solidification casting. At this time, cooling is effected from the direction perpendicular to the direction of the length of continuous fiber, so that needlelike phase is crystallized out in the direction perpendicular to the direction of continuous fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fiber-reinforced metal and a method for producing the same, and more particularly to an aluminum alloy reinforced with continuous fibers and a method for producing the same.

[Conventional technology]

Fiber-reinforced metals (F'l'LM) have excellent strength and rigidity, and have recently been used as various mechanical parts and structural materials. Among these, PR and M, which are made by reinforcing an aluminum composite base material with continuous fibers such as ceramic or carbon, are light, have high rigidity, and have high strength, especially at high temperatures (e.g. 200 to 400 degrees Celsius), so if you use them, you can reduce the weight. With this method, products with excellent mechanical properties at high temperatures can be obtained.

Furthermore, if a casting method such as a high-pressure solidification casting method is used as a manufacturing method for FRM, parts with complex shapes such as automobile parts and precision machine parts can be easily manufactured.

[Problem that the invention seeks to solve]

However, when FRM reinforced with continuous fibers is manufactured by high-pressure coagulation casting, it is difficult for the continuous fibers to be uniformly dispersed in the base material. For this reason, it is necessary to mix 40 to 60 inches of continuous fiber by weight, but if a large amount is mixed, the fibers will come into contact with each other, making it difficult to obtain a gi that satisfies the composite agent (ROM).

Furthermore, the composition of the alloy base material is important for the compatibility between the fibers and the base material, and must be selected depending on the properties of the continuous fibers. In other words, the aluminum alloy base material used for the offering is magnesium (Mg).

Contains silicon (Si), copper (Cu), etc., but for example, when silicon carbide fiber is used as continuous fiber, Mg and Si
Cu deteriorates the fibers and easily produces brittle silicon crystals.
is an FRM that increases the size of crystallized substances in the FRM and contains a large amount of fibers.
This further deteriorates the mechanical properties.

Furthermore, when alumina fibers are used, Sl deteriorates the fibers, and Mg and Cu increase the size of crystallized substances in the FRM. Furthermore, when carbon fibers are used, Mg is good in improving the transverse strength, but it deteriorates the fibers at high temperatures, and Cu and Si coarsen the crystallized substances in the FRM, reducing the transverse strength of the FILM. is low. Therefore, as a base material, it does not produce crystallized substances,
Pure aluminum was said to be suitable because it does not deteriorate the fibers, but F
R and M have a problem in that the strength of the base material itself is low, so that the strength in the direction perpendicular to the length direction of the continuous fibers, that is, the transverse direction, is low.

The present invention is intended to solve the above-mentioned problems in the prior art, and its purpose is to prevent fiber deterioration during the production of PR and M, and to crystallize acicular microcrystals in the base material. The object of the present invention is to provide a fiber-reinforced metal having comprehensively excellent mechanical properties and a method for producing the same.

In other words, the fiber-reinforced metal of the present invention is made of one or two continuous fibers of silicon carbide, alumina, or carbon.In order to solve the problems in the prior art, it is important to control the shape of the crystallized product, that is, the second phase. Become. In this case, there are two methods, for example, one that controls during solidification in the FRM manufacturing process and one that controls by heat treatment of the FRM, but the latter method requires heat treatment at high temperatures to prevent deterioration of the reinforcing fibers. may occur. Therefore, in the present invention, the second phase in the alloy base material is controlled during solidification.

It is necessary to appropriately select the solidification rate and alloy base material composition.

As a result of various studies, the present inventors found that the weight ratio of At to Nii (
If it is a binary alloy containing 15 to 6% manganese (Mn) or a ternary alloy containing manganese (Mn) by weight (Ll to 2%), fine whiskers with a diameter of 15 μm or less are formed in the alloy base material during solidification. It was found that the high-pressure solidification casting method is more effective.

As for the amount of Ni added, α5 to 6% by weight is effective, but it is preferably 2 to 5% by weight.

Further, in order to further improve the strength, a fifth component is added, but in this case care must be taken in selecting the fifth component. for example,
Addition of Cu is undesirable because the crystallized material tends to become coarse particles. On the other hand, if Mn is added, fine whisker-like crystallized substances may be obtained by adding α1 to 2 times by weight.

Continuous fibers that can be used in the present invention can be of any kind as long as they are normally supplied for FRM, such as silicon carbide (SiC), alumina (A403
) or continuous fibers made of carbon (C) are preferred. These continuous fibers may be used alone or in combination of two or more types. Properties such as the type, length, thickness, and cross-sectional shape of the continuous fibers are selected in consideration of the required characteristics of F'll and M to be manufactured, the difficulty of manufacturing, and the like. Particularly favorable results are obtained when ultrafine fibers are used.

By combining the alloy matrix and the continuous fibers, crystallized substances are crystallized in the alloy matrix between the continuous fibers in the form of fine needles (or whiskers), thus reducing the contact between the continuous fibers. .

At! Since the continuous fibers of Os and C are not deteriorated, a high-strength T'RM can be obtained.

Casting is the preferred method for compositing continuous fibers and alloy matrix, and high-pressure solidification casting is particularly effective because it solidifies in a short time and produces fine needle-shaped crystallized substances. It is. A pressure of several hundred ky/crA is easily used during solidification. In addition, by cooling from a direction perpendicular to the orientation direction of the continuous fibers during solidification, fine needle-like (whisker-like) crystallized substances become entangled between the continuous Ifc fibers in a direction perpendicular to the continuous fibers and crystallize. , which acts as a crosslink between continuous fibers, exhibiting excellent interlaminar shear strength.

〔Example〕

The invention will be explained in further detail in the following examples. Note that the present invention is carried out in the following manner ψ0. It is not limited to.

- Silicon carbide fiber (Nicalon made by Nippon Carbon) 1 to 1
It was cut into 50 square pieces, weighed to a volume ratio of 50 yu, and packed into a steel pipe. After preheating this sample at 720°C for 15 minutes in a N2 atmosphere, it was placed in a mold heated to 250°C, and molten At-5% Ni alloy at 720°C was poured into the mold for 25 minutes.
It was pressurized to 500 kf/d using a punch at 0° C. to solidify it.

This is designated as sample A. At-2%Cu-
FRMs with 2% Ni alloy matrix and pure At were also fabricated. These will be referred to as samples B and C.

The results of microscopic observation of FRM sample A taken from the ingot are shown in FIG. 1, and it was found that fine At and Ni whiskers 2 were relatively uniformly distributed in the gaps between silicon carbide fibers 1. Furthermore, using these FRMs, a five-point bending test and an AE measurement were conducted simultaneously. The results are shown in FIG. Although the bending strength of pure AtFRM was 120 kf/-, the number of AE events leading to failure was significantly large. Also, At
Although the number of AE events in the -2% Cu-2% Ni alloys FRMg and lqB decreased compared to pure AtFRM sample C, the bending strength was significantly lower. However, At-5%
When NiFRM test stick At- is used, the bending strength is 0.0
It shows Gin/-, which is similar to that of pure Aυ, and also shows A
The number of E-events was significantly reduced, indicating a reduction in microscopic destruction.

Regarding FRM using this conventional fiber, experiments were conducted with more matrix compositions and the results shown in FIGS. 5 and 4 were obtained.

As is clear from Figures 5 and 4, the At-Ni alloy and the At-Ni-Mn alloy were able to suppress the occurrence of AE without reducing the strength of the F RM. .

Example 2 Carbon fiber (M40 manufactured by Toshi) 3 was cut into a length of 150 g, weighed to have a volume ratio of 60 g, and packed into a steel pipe. This sample was preheated for 15 minutes in a NZ atmosphere at 760°C, placed in a mold heated to 250°, and heated to 760°C.
A molten At-5% Ni alloy was poured into the mold and pressed to 500 mm/cII with a punch at 200° C. to solidify it. Use this as a sample. Also, in the same way, Al, -3Si and A
t-0. %Si alloy F'RM was produced. These are designated as samples E and F, respectively.

Figure 5 shows the structure of the FRM sample taken from the ingot. Many fine Az and Ni whiskers 2 were observed in the fiber gaps. In addition, AE was measured at the same time as the 5-point bending test, and it is clear from Figure 6 that the At-5-chi NiF
``In the case of R, M samples, Al-3-SiFRM sample E
The bending strength was greater than that of , At-z Chi5iFR, and He1 test F, and the number of AE'J downs was small. This is considered to be because the number of microscopic fractures inside the top M, or Nt for one microscopic fracture, became smaller.

〔Effect of the invention〕

As mentioned above, the fiber-reinforced metal of the present invention is made of an aluminum alloy base material to which one or more types of continuous fibers of silicon carbide, alumina, or carbon are added and a predetermined amount of nickel or nickel and manganese. Therefore, during solidification, needle-shaped crystallized substances are generated in the alloy matrix between continuous fibers, and when pure aluminum is used as the matrix, the same strength can be obtained, and when stress is applied. Microscopic fractures were significantly reduced compared to when pure aluminum base material was used, resulting in superior overall properties.

In addition, in the method for manufacturing fiber reinforced metal of the present invention, when manufacturing continuous fibers and base metal using a high-pressure solidification casting method, the continuous fibers are pressurized with a punch in a cold state from a direction perpendicular to the length direction of the continuous fibers. , using a casting strategy that creates a temperature gradient perpendicular to the length of the fiber. Therefore, since the acicular phase of the alloy is crystallized in the alloy matrix in a direction perpendicular to the longitudinal direction of the continuous fibers, it is possible to easily and quickly obtain a fiber-reinforced metal with excellent overall properties. can.

[Brief explanation of drawings]

Fig. 1 is a complete sketch of the metal structure of one embodiment of the fiber-reinforced metal of the present invention, and Fig. 2 shows the deflection and acoustic emission number of each fiber-reinforced metal. Figure 5 is a graph showing the relationship between the amount of nickel added and the bending strength of the fiber-reinforced metal of the present invention, and Figure 4 is the graph showing the relationship between the amount of nickel and manganese added and the bending strength of the fiber-reinforced metal of the present invention. Figure 5 is a graph showing the relationship between the number of metal structures of another embodiment of the fiber reinforced metal of the present invention, and Figure 6 is a graph showing the relationship between the deflection and acoustic emission ring down number of various fiber reinforced metals. It is a graph showing a relationship. 1 blade, patent applicant Toyota Central Research Institute Co., Ltd. (and 1 other person)
′・+5・ tusk 1 figure 2・Achi ship＞I

Claims (5)

[Claims] (1) Consisting of one or more types of continuous fibers of silicon carbide, alumina, or carbon and an aluminum alloy base material containing 0.5 to 6% of nickel by weight, and containing the alloy in the alloy base material. A fiber-reinforced metal characterized by containing an acicular phase. (2) The aluminum alloy base material has a weight ratio of nickel of 0.
5-6% of manganese and 0.1-2% of manganese, and contains an acicular phase of the alloy in the alloy matrix. (3) In compositing continuous fibers and alloy matrix,
The fiber-reinforced metal according to claim 1 or 2, characterized in that a high-pressure solidification casting method is used. (4) When compounding one or more continuous fibers of silicon carbide, alumina, or carbon with an aluminum alloy base material containing 0.5 to 6% nickel by weight using a high-pressure solidification casting method, A fiber characterized in that during solidification, the continuous fiber is cooled in a direction perpendicular to the longitudinal direction of the continuous fiber to crystallize an acicular phase in the alloy matrix in a direction perpendicular to the longitudinal direction of the continuous fiber. Method of manufacturing reinforced metal. (5) The aluminum alloy base material has a weight ratio of nickel of 0.
5-6% of manganese and 0.1-0.2% of manganese.