JPH03183734A - Fiber reinforced metal composite - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention uses silicon carbide fibers with a high modulus of elasticity and high elongation as a reinforcing material, and an alloy consisting of a single metal element or a plurality of metal elements. The present invention relates to a fiber-reinforced metal composite material having good physical properties.

(Conventional technology) Composite materials that have a matrix of metal elements such as aluminum and titanium and are reinforced with inorganic fibers are lighter in production and stronger than the original metal alone.

Several such materials have already been devised, and have the advantage of improving mechanical properties such as elastic modulus and expanding the usable temperature range toward higher temperatures. (Special Publication No. 60-10098.

In particular, when silicon carbide fibers obtained using organosilicon polymer compounds as precursors are used, for example, CVD
Compared to rigid silicon carbide fibers obtained by this method, this method is advantageous in that composite materials with complex shapes can be produced. However, silicon carbide fibers manufactured using conventional precursor methods generally have
Since the organosilicon polymer is cross-linked and rendered invulnerable by oxygen oxidation, the oxygen incorporated at this stage remains in the fiber after firing, and the inherent properties of silicon carbide fibers (molten metal and (low reactivity). In other words, since the m rag contains a large amount of titanium oxide component, a chemical reaction between the metal and the fiber occurs during the production of the composite material with metal or when used at high temperatures after production. Since strength deterioration of the fibers and interfacial fracture occur during material formation, quality reliability of the composite material could not be obtained.

[Problems to be Solved by the Invention] The present invention has been made to solve the problems of the prior art as described above, and when producing a composite material, it is possible to reduce the strength deterioration of reinforcing fibers and to ensure long-term use after production. The purpose is to provide a fiber-reinforced metal composite material that has high reliability and withstands.

[Means for solving the problem] The above-mentioned problem is to solve the above problem by reducing the oxygen content obtained by spinning, infusible, and sintering an organosilicon polymer compound whose main skeleton components are silicon-bonds and silicon-silicon bonds. The composite material of the present invention has silicon carbide fibers of 10% by weight or less, preferably 7% by weight or less as a reinforcing material, and a matrix of a single metal or an alloy or metal compound consisting of a plurality of metal elements such as C. achieved by

The organosilicon polymer compound that is the raw material for the composite material of the present invention is a polymer compound whose main skeleton components are silicon-carbon bonds and silicon-silicon bonds, and is a known compound that is a precursor of silicon carbide. Organosilicon polymer compound (
For example, polycarbosilastyrene copolymer, polycarbosilane, etc. are used. Among these, polycarbosilastyrene copolymers obtained by heat treating and/or ultraviolet treatment of polysilastyrenes as described in Japanese Patent Publication No. 63-39617-ti are particularly preferred. The formation method may be either a melt method or a dry method (solution method), but a melt spinning method is preferable.

Silicon carbide fibers are obtained by spinning the organosilicon polymer compound and then firing it. The firing is preferably performed at a temperature of 800 to 1,400°C for about 1 to 2 minutes in an inert gas atmosphere such as nitrogen or argon gas.
Do time.

Prior to firing, it is preferable to render the fiber obtained from the organosilicon polymer compound invulnerable in a non-oxygen atmosphere.

J "Infusibility in an oxygen atmosphere can be achieved, for example, as follows.

First, halogen is adsorbed and/or acted upon (A
Step), then in a non-oxidizing atmosphere, at a temperature of 200°C or less, a basic substance was applied to at least partially render it invulnerable (Step B). If necessary, heat treatment was performed in an inert gas atmosphere. Promotes infusibility. (Step C).

Examples of the halogen that can be used in Step A include chlorine, bromine, and iodine, with iodine being the most preferred.

The amount of halogen to be adsorbed/acted on is selected within the range of 0.01°C and 150% based on the weight of the fiber,
Particularly preferred is 0.1 to 50% by weight. Adsorption/action methods include a method of placing fibers obtained from an organosilicon polymer compound in halogen gas, and a method of immersing fibers obtained from an organosilicon polymer compound in a solution in which a halogen is dissolved. Although any method can be used, a method in which the fibers are placed in a halogen gas is preferably used industrially. The atmosphere for adsorbing/acting halogen is as follows:
An atmosphere substantially free of oxygen, such as an inert gas atmosphere or a vacuum atmosphere, is preferred.

The temperature at which the halogen is adsorbed/acted on the fibers is usually 50°C or higher and a temperature at which a liquid layer does not form, preferably 100°C to (polymer melting point -10°C) in order to increase treatment efficiency. Adopted.

Next, a chlorinated substance is applied in a non-oxidizing atmosphere to the fiber obtained from the organosilicon polymer compound on which 1 VL of halogen has been applied and acted upon in this way (Step B).
It is preferable.

Examples of the basic substance that can be used in Step B include ammonia, methylamine, and ethylenediamine, with ammonia being the most preferred.

There are various methods for making these tU-based substances act, but usually the basic substance is made into a gas,
It is preferable to use 1↑ in the coexistence/absence of an inert gas, and in either case, it is necessary to conduct the reaction under conditions substantially free of atomizing elements.

In this step B, the amount of time the basic substance is applied varies depending on the indigo of the halogen adsorbed to the fiber in the previous step, but it is preferable to apply the basic substance in sufficient excess to the amount of halogen. On the other hand, a range of equivalents to 400 equivalents is preferably employed. The temperature at which the basic substance is applied is from room temperature to 200°C. If this temperature is too high, fusion of fibers will occur, which is not preferable.

In this way, the fibers treated with a halogen and then with a basic substance are already significantly infusible, but the infusibility is made more complete by heat treatment in a substantially inert gas atmosphere. (Step C).

The heat treatment for this purpose is preferably carried out in an inert gas (nitrogen, etc.) atmosphere at a temperature of about 200 to 700°C, preferably 200 to 600°C, for 1 minute to 3 hours from the viewpoint of operability. be done.

Depending on the infusible state after basic substance treatment (Step B),
It may be immediately subjected to firing without performing this heat treatment in an inert atmosphere (step C).

Firing is performed by heating the fibers after the infusibility treatment in an inert gas atmosphere for about 80 minutes.
This is carried out by heating at 00° C. or higher, preferably 1000 to 1500° C., and the organosilicon polymer compound constituting the invulnerable m-fiber is converted into ceramics mainly composed of silicon carbide.

The silicon carbide fiber used in the present invention is
It includes various fiber shapes such as multifilament 1, monofilament, tow, felt, strand, cloth, and chopped.

The oxygen content in the silicon carbide fiber used as a reinforcing material in the present invention must be 10% (by weight) or less, and preferably 7% (by weight) or less.

The oxygen content of conventional silicon carbide fibers is in the tens of thousands (
weight)? ≦, and such a thing cannot achieve the purpose of the present invention. That is, when the oxygen content in the 48 fiber turns -L from 10 (weight) 9≦, at the metal-fiber interface at high temperature, Mainly, a reduction reaction occurs due to the metal element of the silicon oxide component, and the strength of the fibers deteriorates significantly, resulting in a decrease in the performance of the composite material.

Therefore, it is necessary that the oxygen content contained in the silicon carbide fiber is 10 (weight J = 9≦).

Reduction of the oxygen content in silicon carbide fibers is achieved by employing the above-mentioned non-fusible method of sequentially using a halogen and a basic substance. Conventional air #! In the infusible method using i1H, it is extremely difficult to reduce the oxygen content remaining in the fibers to 10% (31% by weight) or less.

In the present invention, among the fibers obtained in this way, tensile modulus of elasticity of 15"r'/'- or more and elongation of 1.8%
It is preferable to use the above silicon carbide fibers as a reinforcing material.

If the tensile modulus is less than 15 T/mm2, the rigidity of the composite material is insufficient, and it is not favorable for the toughness and impact resistance when made into a composite material. Also, if the elongation is less than 1.8%, the composite material It is unfavorable in terms of toughness and impact resistance when fabricated, and often results in poor weavability.

In addition, the silicon carbide fiber obtained by the above method usually contains 1.5 to 2□5 times as much carbon (by weight) as silicon, and is characterized by a higher carbon content than conventional silicon carbide fibers. .

In the present invention, the thickness of the silicon carbide fiber is
A suitable thickness is 3 μm to 30 μm, preferably 5 μm to 20 μm.

When producing the composite material of the present invention, the silicon carbide fiber used as a reinforcing material is processed into any form depending on the purpose. That is, a long fiber wire 1 pre-impregnated with 7 Trix 1 is cut into an arbitrary length.
Hecut fiber can be used in the form of woven or knitted fabrics such as plain weave, satin weave, or mock-satin weave, ropes, bag knits, etc. Furthermore, a woven or knitted fabric can be produced and used by mixing it with metal fibers. Moreover, the fiber can also be used as it is without being processed.

On the other hand, in the present invention, a single metal element, an alloy consisting of a plurality of metal elements, or an intermetallic compound is suitably employed as the metal 71.

The melting point of these matrixes is 200°C or above 2000°C.
゛C or less is preferable. If the melting point is below 200°C, the temperature at which it can be used is too low even if it is reinforced with silicon carbide fibers. Furthermore, if the melting point is 2000° C. or higher, it is necessary to set up a high temperature (near the melting point (g) environment) in order to produce a composite material, which is undesirable from the viewpoint of process equipment and cost.

The specific gravity of the matrix is preferably 1.5 or more and 20 or less,
In other words, normally, in order to be used in the matrix of composite materials, it must have a strength suitable for the purpose as a structural forest material, and at a low density of 1.5ty'cj or less, the bonds between molecules or atoms are weak, resulting in 71 -Rix is not strong enough. Furthermore, substances with a density exceeding 20 g/cJ inevitably have a high melting point, making it difficult to produce composite materials. moreover,
With a high-density matrix, it is difficult to achieve the effect of weight reduction, which is the original purpose of ζ composite.

Preferably employed matrices include Mg, ri, AI, Cu, Fe, Cr as a single metal element.
, Ha, Si.

Examples include metals such as CO1. As an alloy, it is
Binary gold such as Ti-Cu, ^1-Cu, Nb-Ta.

An alloy having a single component composition such as a ternary alloy such as T+-1:u-^1 is employed. Nb as an intermetallic compound
, AI, Nb28I, Nb^13, 80312, etc.

Composite formation of these matrix yx and silicon carbide fibers is achieved under heat and pressure.

Heating conditions vary depending on the melting point of the matrix, but generally the solid phase of the matrix &! Composite formation at a temperature below the 6 solidus line, which is set in the vicinity of (the line that separates the two states of liquid phase and solid phase in a phase diagram), is called a solid phase forming method. In principle, this is a method that uses plastic deformation of the matrix to create a composite by diffusion bonding under pressure.
HIP method.

There are hot rolling methods, slip casting methods, etc.

On the other hand, compositing at a temperature above the solidus line is called liquid phase molding. This is a spinning method in which the matrix is brought into contact with the fibers in a liquid phase, molded, and then cooled.

The liquid phase can be opened using the breath method, autoclave method, etc. In the method described above, the pressure is applied for 1° minute, which is necessary to achieve the purpose of compositing, and if the pressure is too strong, the fibers may break, which is not preferable.

Thus, in the present invention, the composite material is one of the above materials.
It is made by a unique method.

In the composite material of the present invention, the silicon carbide fiber as a reinforcing material has a volume of 20 to 80 M 10 r, preferably L
Yo 30-60 volume? It is preferable that the amount is less than 20% by volume, and the fiber reinforcing effect is not sufficient.

If it exceeds 80% by volume, it becomes difficult to uniformly disperse the fibers in the matrix, and the adhesion between the 71-Lix fibers becomes insufficient, resulting in a decrease in strength.

The composite material of the present invention obtained in this manner can be used in parts such as airframes, engines, nozzle blades, gas turbines, and fan blades of various transport aircraft in the aviation and space fields, and in general applications such as engines for automobiles, ships, etc. It can be used in a wide range of applications such as shirts, crank parts, golf club heads, club shafts, and other sports equipment.

[Example] The present invention will be explained in more detail with reference to Examples below.

The method for measuring the oxygen content in the fibers is as follows.

Weigh out a certain amount of sample (approximately 20 cm) into a (Sn) capsule and place it in a graphite crucible.
After adding zinc, nib gel), inert gas (Ice)
A large current is passed through the graphite crucible in an air stream to heat the crucible and instantly melt the sample. Oxygen in the sample is graphite (carbon)
After the carbon monoxide (CO) produced as a result of the reaction is passed through a copper oxide catalyst layer and converted into carbon dioxide, oxygen is determined by measurement with an infrared detector.

Practical Kneeling Example 1 Polysilastyrene obtained by polymerizing equimolar amounts of dichlorodimethylsilane and dichloromethylphenylsilane at 110°C using a sodium dispersed catalyst in a toluene solvent was exposed to an inert gas at 400°C for 60 minutes. (Nitrogen) to obtain a polycarbosilastyrene copolymer with a softening point of 3°C. This copolymer was solution-spun at 290° C., and the obtained polycarbosilastyrene copolymer MIi fibers were continuously supplied to an iodine treatment apparatus having a gaseous iodine supply port maintained in a nitrogen atmosphere. The inside of the iodine gas treatment equipment is 180
It was maintained at 0.degree. C. and fed continuously with iodine in an amount corresponding to % by weight of the fibers fed. The iodine-treated fibers continuously taken out from the apparatus are then kept at room temperature and contain 3!8 times ammonia gas per 8 times iodine. v! The mixture was then introduced into a basic substance treatment unit, where it was treated with ammonia.

The ammonia-treated fibers continuously taken out from the apparatus were then heated to 400° C. in a nitrogen atmosphere to obtain invulnerable fibers.

The infusible fibers were then continuously heated for 1.2 hours under a nitrogen atmosphere.
It was fired at 00°C to obtain silicon carbide fibers.

The oxygen content of the silicon carbide fiber was 5.3% by weight. The tensile strength of this fiber is 381 kg/m
m2, the tensile modulus was 20'l"/mm21, and the elongation was 1.9%.

In order to evaluate the reactivity of the silicon carbide fibers and light metals at high temperatures, aluminum was used as the light metal.
1, the following evaluation experiment was conducted.

Silicon carbide fibers on which aluminum had been vacuum-deposited were heated at 700° C. for a certain period of time in a nitrogen atmosphere. After cooling, the fibers were immersed in a 10% aqueous sodium hydroxide solution to remove aluminum, and then a tensile test was conducted to evaluate strength deterioration before and after heating.

As a result, the strength retention rate was 95% when heated at 700°C for 2 minutes, and the strength retention rate was 70% when heated at 700°C for 10 minutes.

Next, the silicon carbide fibers were used as a reinforcing material, and aluminum ram (purity of 99.9% or more, melting point of 660°C) was used.

A composite material having a matrix of specific gravity 2.7 r/cJ was produced by high-pressure casting.

That is, first, silicon carbide fibers were placed in a bell-shaped mold, and heated and kept at 300"C in advance. Molten aluminum (solution) prepared separately was injected into the mold at once using an injector, and then cooled. This composite material was cut to make a test piece for tensile testing.The blood cut of the test piece was a perfect circle and the cross-sectional area was 0.2-. The volume fraction (Vf) of silicon carbide fibers in the test piece was 40%.

When a tensile test was performed on the test piece, it was 101 qr/mm2 for the original case of only aluminum, but the tensile strength of the test piece reinforced with silicon carbide fiber was 61 kg/'-, which was a significant increase. The mi tension effect was confirmed. Further, when the fracture surface was visually observed, no pull-outs were observed, and the adhesion between the matrix and silicon carbide 1a1i was good.

Comparative Example 1 A polycarbosilastyrene copolymer (softening point % 3°C) synthesized by the method shown in Example 1 was subjected to 7B melt spinning at 290°C. The obtained polycarbosilastyrene fiber was
It was heat-treated in air at 0°C for 2 hours, and then heated at 400°C in a nitrogen atmosphere to obtain an infusible fiber. The infusible fibers were fired at 1,200° C. in a nitrogen atmosphere to obtain silicon carbide fibers.

The oxygen content of the silicon carbide fiber is 13.0
The weight percent and tensile strength were 300 hg/mm2, the tensile modulus was 13 T/J, and the elongation was 2.3%.

When the evaluation experiment shown in Example 1 was conducted on the silicon carbide fiber, the strength retention rate was 70% when heated at 700°C for 2 minutes, and the strength retention rate was 30% when heated at 700°C for 10 minutes.

Next, using the silicon carbide fiber, Example 1
An aluminum-silicon carbide fiber composite specimen was prepared according to the method shown in .

The Vf of this test piece was 35%, the tensile strength was 45 kg,
/J. When the fracture surface of the sample was observed after the test, a slight pull-out was observed.

Comparative Example 2 6 ft of commercially available silicon carbide wire (oxygen content 12
When the evaluation experiment shown in Example 1 was conducted on the following properties (weight%, tensile strength: 280 kg/' twd, tensile modulus: 17 T/mm, elongation: 1.65%), it was found that 700°C.
The strength retention rate was 60% after heating at 700"C for 10 minutes, and the strength retention rate was 309≦ after heating at 700"C for 10 minutes.

Using the silicon carbide fibers, an aluminum-silicon carbide fiber composite material was prepared according to the method shown in Example 1. This test piece had a vf of 40% and a tensile strength of 49+r/'-.

When the fractured surface of the sample after the test was observed, some pull-out was observed.

Example 2 Dichloro17 dimethylsilane in 1-toluene solvent, Nato9
Polydimethylsilane obtained by polymerization reaction at 110°C in the presence of a 915% dispersed catalyst was heated in an autoclave for 40°C.
A polycarbosilane having a softening point of 0°C was obtained by heat treatment at 0°C for 15 hours in an inert gas (nitrogen). This polycarbosilane was melt-spun at 265° C., and the resulting polycarbosilane fiber was subjected to infusible firing in the same manner as in Example 1 to obtain silicon carbide fiber.

The oxygen content of the silicon carbide fiber was 4.9% by weight. The tensile strength of this fiber is 300 kg/'
-, the tensile modulus was 15T/i, and the elongation was 2χ.

When the evaluation experiment shown in Example 1 was conducted on the silicon carbide fiber, the strength retention rate was 85 when heated at 700°C for 2 minutes, and the strength retention was 6 when heated at 100°C for 10 minutes.
It was 0%.

Using the silicon carbide mu, an aluminum-silicon carbide fiber composite test piece was prepared according to the method shown in Example 1. The Vf of this test piece is 40%
The tensile strength was 58 kg/mm2.

When we observed the cross section of the test piece, we found that it was clear (ρu1-o
ut) was not recognized.

"Effects of the Invention" The composite material of the present invention has high tensile modulus and elongation, and uses silicon carbide fibers with reduced oxygen content as a reinforcing material, so it is easy to work with during production. In addition, there is little deterioration in fiber strength due to reaction with the matrix, so it is possible to design materials with high reliability.Such composite materials are used for sports equipment, aviation, space equipment materials,
General transport aircraft.

It can be widely used as a building material.

Claims (4)

[Claims] (1) Silicon carbide with an oxygen content of 10% by weight or less obtained by spinning, infusible, and sintering an organosilicon polymer compound whose main skeleton components are silicon-carbon bonds and silicon-silicon bonds. A fiber-reinforced metal composite material that uses fiber as a reinforcing material and a matrix of a single metal or an alloy or metal compound made of multiple metal elements. (2) The fiber-reinforced metal composite material according to claim (1), wherein the silicon carbide fiber has an oxygen content of 7% by weight or less. (3) Tensile modulus of silicon carbide fiber is 15T
/mm^2 or more, and elongation is 1.8% or more. Claim (1)
Or the fiber reinforced metal composite material according to (2). (4) The melting point of the matrix is 200°C to 2000°C,
The fiber-reinforced metal composite material according to claim 1, which has a specific gravity of 1.5 to 20.