Fiber-reinforced metallic composite material

DETAILED DESCRIPTION OF THE INVENTION The composite material of this invention comprises as a matrix a metal or alloy having a lower melting point and being chemically inactive and as a reinforcement inorganic fibers of 15 to 70% by volume, which is characteristic in that the alloy composing the matrix contains 0.
01 to 10% by weight of one or more metals of group IA or group IIA (except beryllium) in the periodic table in addition to the matrix metal having a lower melting point and being chemically inactive.
The inorganic fibers used in this invention include carbon fiber, silica fiber, silicon carbide fiber, boron fiber, alumina fiber, and the like.
The inorganic fibers are contained in the composite material of this invention in an amount of 15 to 70% by volume based on the whole volume of the composite material.
When the amount of the fibers is less than 15% by volume, the desired reinforcing effect cannot sufficiently be achieved, and on the other hand, when the amount is over 70% by volume, the strength of the composite material is rather lowered due to the mutual contact of fibers.
The fibers may have any form, such as long fibers or short fibers, and any form of fibers can be used depending on the desired utilities of the product.
These forms of fibers may be used alone or in combination thereof.
The fibers are applied to in various orientations, such as unidirectional crossplying, random orientation, and the like in order to give the desired mechanical strength and elasticity.
Among these inorganic fibers, the most preferable fiber for achieving the desired reinforcing effect is alumina fiber as disclosed in Japanese Patent Second Publication (Kokoku) No.
13768/1976, i.
e.
the alumina fiber having an alumina (Al.
sub.
2 O.
sub.
3) content of 72 to 100% by weight, preferable 75 to 98% by weight, and a silica (SiO.
sub.
2) content of 0 to 28% by weight, preferably 2 to 25% by weight, and exhibiting substantially no reflection by X-ray diffraction due to the .
alpha.
-Al.
sub.
2 O.
sub.
3 structure