Consolidation of fiber materials with particulate metal aluminide alloys

Abstract

A process is disclosed for fabricating a metal aluminide composite which comprises providing a metal aluminide, such as titanium aluminide, or a titanium aluminide alloy, and a reinforcing fiber material, such as silicon carbide fiber, and placing an interlayer or diffusion barrier layer in the form of a metal selected from the group consisting of silver, copper and gold, and alloys thereof, between the metal aluminide and the reinforcing fiber material. The interlayer metal can be a foil of the metal or in the form of a coating, such as a silver coating, on the reinforcing fiber material. The metal aluminide, the reinforcing fiber material, and the metal interlayer, e.g., in the form of a packet of a plurality of alternate layers of metal aluminide alloy and reinforcing fiber material, each layer being separated by the metal interlayer, is pressed and heated at an elevated temperature, e.g., ranging from about 900.degree. to about 1200.degree. C., at which diffusion bonding occurs. The diffusion barrier metal, e.g., silver, dissolves in the metal aluminide during consolidation of the metal aluminide matrix with the reinforcing fiber material. A layer of tantalum on silver can be employed as a second diffusion barrier layer, and a third layer, such as titanium alloy, can be applied over the tantalum layer, for increased effectiveness of the diffusion barrier, and preventing crack initiation.