JPS61266530A - Composite material - Google Patents

Abstract

PURPOSE:To obtain a composite material having high toughness as well as high strength as heat resisting structural material by providing a composition consisting of a ceramic fiber and an Ni3Al intermetallic compound. CONSTITUTION:The Ni3Al intermetallic compound-ceramic fiber composite material is made by combining at least one or more kinds among ceramic short fibers or whiskers selected from minerals with the Ni3Al intermetallic compound. As to the above ceramic fibers or whiskers, minerals such as oxides, nitrides, borides, etc., or their composite compounds are used and particularly, by use of oxide types, a high-density composite material can be obtained because of its low chemical reactivity with Ni3Al and relatively superior wettability. As the above oxide types, Al2O3 is most preferably used. Further, it is preferable that the mixing ratio of the ceramic fiber is 104n60vol% and particularly in the range from 20-40%, the greatest reinforcing effect can be produced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a NimA1 ceramic fiber composite material having high strength and high toughness as a heat-resistant structural material.

[Conventional technology]

In recent years, there has been a movement to use intermetallic compounds as heat-resistant structural materials, and among these, Ni has a strength peak on the high temperature side.
5Al is attracting particular attention.

However, since high-temperature strength of Ni3Al alone is not necessarily sufficient, there are attempts to strengthen and improve high-temperature strength by combining Ni3Al with ceramics. for example,
Composite material of NimAl1 and carbon fiber receives No. 3 US patent
953647.

In addition, a composite material in which NiA1, a similar intermetallic compound, is dispersed and strengthened with ThOz particles is disclosed in U.S. Patent No. 3,520,675.
Furthermore, a composite material in which NiA1 intermetallic compound KA1z01 particles or N10 particles are dispersed has been proposed.

[Problem to be solved by the invention]

However, in conventional composite materials, a particle-dispersed type cannot originally expect a large reinforcing effect, and even a carbon fiber-reinforced type has difficulty in obtaining sufficient strength. After conducting various studies on this point, it was found that this is probably because the carbon fibers react with Nism 1 during the manufacturing process, which damages the fibers and significantly inhibits the reinforcing effect. Therefore, there was a problem in that even if the amount of fiber was increased, sufficient strength could not be obtained.

The present invention eliminates the above-mentioned drawbacks by using specific ceramic short fibers or whiskers as a reinforcing material for Ni3Al, which was not known in the past, and provides a new high-strength Ni3Al composite material with less strength deterioration due to reactions. The purpose is to

[Means for solving problems]

The present invention was made in order to solve the above-mentioned problems, and consists of a Ni3Al intermetallic compound combined with one or more types of short ceramic fibers or whiskers selected from inorganic materials. The present invention provides a ceramic fiber composite material.

Examples of the ceramic fibers or whiskers used in the present invention include inorganic materials such as oxides, nitrides, and borides, and composite compounds thereof. Among them, the oxide type is Ni3Al. It has been found that a high-density composite material can be obtained due to the low chemical reactivity with and relatively good wettability. Although it is not clear why oxide systems are suitable, Ni
This seems to be due to the formation of thermodynamically stable NiO at the interface between 5Al and the fiber. Among the oxides, especially A1101,
ZrOx showed good results. Furthermore, mu-IgOi showed the best results among them.

Normally, AltOn and Zr erectile fibers contain a few chills of 50% S.
Although B10x contains iO, it is relatively easy to react with Ni3Al, and in that sense, it is desirable to have a small content, but on the other hand, if B10x does not contain any 1310m, the wettability involved in bonding with Ni3Al will decrease. There is a problem that the reinforcement effect decreases. As a result of consideration, EliOm is about 5 cm,
Specifically, it has been found that A1zOa fibers and Zr0z fibers containing 3 to 8% by weight are preferable.

Ceramic fibers have a diameter of 1 to 100 μm.
, and the length is in the range of 10 μm to 111 lI, but in particular, the diameter is 3 to 20 μm and the length is in the range of 50 to S.
A shape of OO μm is preferable because it can exhibit the highest reinforcing effect.

The mixing ratio of ceramic fibers in the present invention is 1
A range of 0 to 60 volume is preferable, and the greatest strengthening effect can be especially achieved in the range of 20 to 40 volume. Contamination ratio is 10
If it exceeds 60%, it becomes difficult to obtain a compact body, and the strength decreases due to warpage.

The melt stirring method, molten metal forging method, or powder metallurgy method can be applied as a means of manufacturing composite materials, but powder metallurgy method, which is the only method that can be manufactured at temperatures below the melting point of intermetallic compounds, is particularly effective because it allows the reaction between fibers and matrix to occur. It is preferable because it can be suppressed and the fibers can be uniformly dispersed.

As a raw material for NilAl synthesis when produced by powder metallurgy, Ni3Al powder, a mixed powder of Ni-Al alloy powder and N1 powder, or a mixed powder of N1 powder and A1 powder can be used.
In the case of a mixed powder of 1 flour and A1 flour, soft A1 powder is produced during pressurized manufacturing.
is preferable since it acts as a pressure reliever and can minimize damage to the fibers.

As a manufacturing method, any of the usual hot press method, pressureless sintering method, or a combination of both can be applied. The manufacturing atmosphere is preferably reducing or vacuum in order to prevent acidification of the red powder.

To produce the N1jA1mm ceramic lIt fiber composite material of the present invention, 10 to 60 volumes of ceramic fibers are mixed with the N1jA:L synthetic raw material powder, the mixed powder is filled in a graphite mold, and the mixture is heated in argon, hydrogen, or 1000 or more, preferably 1200 to 1300" under pressure or non-pressure in a non-oxidizing or reducing atmosphere such as vacuum
The composite material can be manufactured by heating in the temperature range of e.

The Ni1Al-Selantsu fiber composite material produced in this way has high high-temperature strength, high toughness, high oxidation resistance, and high hardness, so it is suitable for a wide range of applications such as turbine parts, heat-resistant spring materials, wear-resistant materials, etc. It can be used for

[Effect]

In the present invention, the ceramic fiber acts as a reinforcing material for the Ni11 matrix. The reinforcing mechanism is that the stronger ceramic fibers, which are firmly bonded to the matrix, play the role of the IJ sock.

In particular, oxide fibers such as Altos and ZrO2 are
@ It has the advantage that it has low reactivity with A'1 and the fibers are not easily eroded, and has good wettability with NinA1.
It is thought that the reinforcing effect is effectively expressed because it is strongly bonded to the matrix. The reason why the oxide system has low reactivity is not necessarily clear, but it is thought to be because thermodynamically stable NiO is formed at the interface between N i m A1 and the oxide fiber.

〔Example〕

Example I 86.7 weight tS of N1 powder and the important part of A1 were mixed in ethanol using a wet ball mill method, and an amount corresponding to 20 - of the total volume of N1 powder and L powder with a diameter of 3 to 5 am and a length was added. 40
0~500 JJm 1. YiOs short fibers (containing about 5 iOz components, trade name: Safil) were added, mechanically stirred, and then dried.

This mixed powder of N1 powder, A1 powder, and Safil was put into a graphite mold, and the pressure was 3 s o K4/al, and the temperature was 1300°C.
, hot pressed in an Ar-2o%H2 atmosphere for 2 hours. The composite thus obtained has a stone tensile strength of 80 Kf/rd at room temperature and a tensile strength of 6 at 80 otK.
2 to 4/d, Vickers hardness 450HV, fracture toughness I
C15MN/”/, m.

Examples 2 to 7 The results of composite materials obtained in substantially the same manner as in Example 1 except for changing the type and content of fibers were as follows. (For whiskers, we used whiskers with a diameter of approximately 1.5 μm and a width of 100 to 500 μm.) For comparison, we used the data of Ni#A:L single material and carbon fiber composite material as reference. 395364
7 has been cited and shown.

〔Effect of the invention〕

The composite material of the present invention not only has the effect of significantly increasing strength and hardness compared to N1jA1 single material, but also has superior effects compared to composite materials with carbon fiber, and is particularly effective against oxidation. Composite materials made of short fibers have a remarkable effect in comparison.

Claims (11)

[Claims] (1) Composite material consisting of ceramic fiber and NisAl intermetallic compound (2) The composite material according to claim 1, wherein the ceramic fibers are short fibers or whiskers. (3) Ceramic fibers have a diameter of 1 to 100 μm and a length of 1 μm.
The composite material according to claim 2, which has a thickness of m to 1 mm. (4) The composite material according to any one of claims 1 to 3, wherein the ceramic fibers are made of one or more selected from oxides, nitrides, carbides, and borides. (5) The composite material according to claim 4, wherein the ceramic fibers are short oxide fibers or whiskers. (6) Ceramic fiber is Al_2O_3 or ZrO_2
The composite material according to claim 5, which is a fiber. (7) Ceramic fiber contains 3-8% SiO_2 by weight%
Composite material according to claim 6, which is Al_2O_3 or ZrO_2 fiber containing (8) The composite material according to claim 6 or 7, wherein the ceramic fiber is Al_2O_3. (9) Ceramic fiber is SiC, Si_3N_4 or B
The composite material according to claim 4, which is a whisker selected from _4C. (10) The composite material according to any one of claims 1 to 9, containing 10 to 60% by volume of ceramic fibers. (11) Ceramic fibers produced by powder metallurgy are N
Composite material according to claim 10, which is formed by uniformly dispersing and containing i_3Al intermetallic compounds.