JP3023808B2 - Particle reinforced metal matrix composite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a particle-reinforced metal matrix composite member used as various structural members.

[0002]

2. Description of the Related Art Conventionally, as a composite member of this kind, a composite particle obtained by subjecting a ceramic particle to a metal coating treatment and coating the surface of the composite particle with a metal layer is used. Are known.

[0003]

However, the conventional composite particles have low bonding strength between the ceramic particles and the metal layer due to poor wettability between the ceramic particles and the metal layer, and also have a large difference in their thermal expansion coefficients. Therefore, there is a problem that the strength of the composite member, particularly the high-temperature strength, cannot be improved as intended.

[0004] In view of the above, it is an object of the present invention to provide a high-strength composite member using composite particles in which the bonding strength between ceramic particles and a metal layer is improved and the difference in the coefficient of thermal expansion between the two is reduced. And

[0005]

In the particle-reinforced metal matrix composite member according to the present invention, the metal layers of the composite particles in which a metal layer having a single crystal structure is grown on the surface of ceramic particles having a single crystal structure are joined to each other. It is characterized by the following.

[0006]

FIG. 1 shows a particle reinforced metal matrix composite member (hereinafter referred to as P
RM).

The apparatus has a main chamber 1 and a sub-chamber 2 provided below the main chamber 1 and both chambers 1 and 2 are connected via a duct 3 and a nozzle 4 attached to the lower end thereof. Communicate. A W electrode 5 inserted in the main chamber 1 and a Cu hearth 6 installed in the main chamber 1 are connected to a power supply 7. A movable substrate 8 is arranged in the sub-chamber 2 and faces the nozzle 4. The main chamber 1 is connected to an atmosphere gas supply 9, while the sub-chamber 2 is connected to a vacuum pump 10.

[0008] The following procedure is employed in the manufacture of PRM. (1) The metal lump M is put in the hearth 6. (2) The pressure inside the sub-chamber 2 is reduced by operating the vacuum pump 10. (3) The atmosphere gas supply source 9 is operated to supply the atmosphere gas into the main chamber 1, and the atmosphere gas is injected from the nozzle 4 into the sub-chamber 2 through the duct 3. (4) A voltage is applied between the W electrode 5 and the hearth 6 to generate an arc discharge, thereby melting the metal lump M and generating a metal vapor.

By reacting the metal vapor with the atmospheric gas, ultrafine composite particles having the surface of the ceramic particles covered with a metal layer are produced. In the process of producing the composite particles, first, a reaction between the metal vapor and the atmospheric gas generates ceramic particles having a single crystal structure, and then the metal vapor attached to the surface of the ceramic particles grows epitaxially to form a single crystal structure. The phenomenon that a metal layer is generated occurs. (5) The composite particles are ejected from the nozzle 4 to the substrate 8 through the duct 3 and are deposited on the substrate 8. At this time, bonding between the metal layers is performed, and a PRM in which ultrafine ceramic particles are uniformly dispersed in a metal matrix is manufactured.

In this case, an extrusion process or a sintering process under pressure may be adopted as the next process. Alternatively, the composite particles may be collected from the nozzle 4 and used alone.
Alternatively, the PRM may be manufactured by bonding the metal layers of the composite particles to each other by performing sintering processing after powder compaction, extruding, or the like using other single metal particles in combination. When the mixed particles of the composite particles and the metal simple particles are used, the PRM of the ceramic particles present in the composite particles is used.
The volume fraction Vf with respect to the whole is set to 1% or more.

As the metal lump M, a simple substance or an alloy of Fe, Al, Ti or the like is used.

As the atmosphere gas, N ₂ gas, O ₂ gas, CH ₄ gas, diborane gas or the like is used, and Ar gas is used together if necessary. Thus, the ceramic particles are nitrides, carbides, borides or oxides of said metals.

Next, a specific example will be described.

In the above-described manufacturing method using the apparatus shown in FIG. 1, pure Al is used as the metal lump, and N ₂ gas having a purity of 99.99% and Ar gas having a purity of 99.99% are used as the atmosphere gas. The pressure in the chamber is 10 ^-2 Torr,
The composite particles were produced under the condition of a nozzle diameter of 0.8 mm.

FIG. 2 is a micrograph (magnification: 300,000) showing the crystal structure of the composite particle P, and FIG. 3 is a schematic cross-sectional view of the composite particle P corresponding to FIG. The composite particles P
It is composed of octahedral AlN particles (ceramic particles) c having a single crystal structure and a hexagonal cross section, and octahedral Al layers (metal layers) m having a hexagonal cross section and a single crystal structure covering the surface thereof.
The Al layer m has grown epitaxially on the surface of the AlN particle c, and the crystal orientation relationship between the two m and c is [111] Al //
[001] AlN, [101] Al // [110] Al
N, [121] Al // [110] AlN. Thereby, the bonding strength between the AlN particles c and the Al layer m increases.

Table 1 shows the relationship between the gas partial pressure and the composite ratio in the various composite particles P. The composite ratio is shown in FIG.
In, when the distance between the one edge portion and the center of the Al layer m of the composite particles P and d _1, also the distance between the one edge portion of the center and AlN particles c was d _2, d ₂ / d ₁
Is represented by

[0017]

[Table 1] From Table 1, it can be seen that the composite ratio increases as the N ₂ gas partial pressure increases. In this case, if the particle diameter of twice the distance d ₂ of AlN particles c, the particle size of AlN particles c forty to twelve
0 nm, which is very fine.

Next, various composite particles and Al alloy particles (20
24 materials) and a pressing force of 4 t / cm ²
A green compact having a diameter of 80 mm and a length of 70 mm is formed at 450 ° C., an extrusion ratio of 13.0, and an extrusion speed of 1 mm.
Each PRM was manufactured by extrusion under the conditions of / sec.

FIG. 4 shows the relationship between the temperature and the tensile strength of various PRMs. In the figure, the line a indicates the tensile strength σ _B of the PRM according to the present invention. In this case, the volume fraction Vf of the AlN particles is 20%, and the particle size of the AlN particles is 100 nm. The line b represents the strength sigma _B Tensile Comparative Example PRM, the comparative example PRM, the using more becomes mixed particle composite particles and Al alloy particles of SiC particle surfaces were coated with Al layer (2024 material) It is manufactured by the same method as that described above. In this case, the volume fraction Vf of the SiC particles is 20%, and the particle size of the SiC particles is 4 μm.

FIG. 4 shows that the PRM according to the present invention is comparative example P
It can be seen that the high-temperature strength is higher than that of RM.

This is because in the PRM according to the present invention,
Since the Al layer having a single crystal structure is epitaxially grown on the surface of the AlN particle having a single crystal structure and their crystal orientations are aligned, the bonding strength between the AlN particle and the Al layer, and thus between the AlN particle and the Al alloy matrix, is increased. Is high, the thermal expansion difference is small, and the AlN particles are fine and uniformly dispersed in the Al alloy matrix.

Comparative Example PRM has a large difference in the coefficient of thermal expansion between the SiC particles and the Al layer, and delamination occurs at a high temperature.

The composite particles in the present invention include those in which the surface of the ceramic particles is not completely covered with a metal layer.

[0024]

According to the present invention, it is possible to provide a high-strength particle-reinforced metal matrix composite member having high bonding strength between a ceramic particle and a metal matrix by using composite particles having the above specific structure. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an apparatus for manufacturing a particle-reinforced metal matrix composite member according to the present invention.

FIG. 2 is a micrograph showing a crystal structure of a composite particle.

FIG. 3 is a schematic cross-sectional view of a composite particle.

FIG. 4 is a graph showing the results of a tensile test.

[Explanation of symbols]

 P Composite particles c AlN particles (ceramic particles) m Al layer (metal layer)

Continued on the front page (72) Inventor Akihisa Inoue 11-806 Kawauchi Residence, No. Kawauchi, Aoba-ku, Sendai, Miyagi Prefecture Inventor Takeshi Masumoto 3-8-22, Uesugi, Aoba-ku, Aoba-ku, Sendai City, Miyagi Prefecture (72) Inventor Jun Sasahara 1-4-1 Chuo, Wako-shi, Saitama Pref.Honda R & D Co., Ltd. (72) Inventor Katsutoshi Nozaki 1-4-1 Chuo Wako-shi, Saitama Pref. Honda R & D Co., Ltd. (72) Inventor Masashi Yamaguchi 3-24-23 Kano, Taihaku-ku, Sendai-city, Miyagi Prefecture (56) References JP-A-63-216919 (JP, A) JP-A-3-146627 (JP, A) JP-A-4-502347 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C22C 1/09 C22C 1/10

Claims (1)

(57) [Claims] 1. A particle-reinforced metal matrix composite member comprising a composite particle obtained by growing a metal layer having a single crystal structure on the surface of a ceramic particle having a single crystal structure and joining the metal layers to each other.