Interface control and design for SiC fiber-reinforced titanium aluminide composites

Abstract

The effectiveness of several coating systems which were used as a diffusion barrier for the SiC fiber-reinforced titanium aluminide composites was investigated. TaC, TiC, TiB2, B, C/graded TiB2, and Ag/Ta were applied to the SiC fiber via chemical vapor deposition and physical vapor deposition. The interfacial compatibility, interfacial stability, thermal residual stress, interfacial bond strength, and the transverse fracture behavior of the composites with coated fibers were characterized and determined. The results show that none of the above coating systems can satisfy the requirements for a strong, tough, and damage-tolerant SiC fiber-reinforced titanium aluminide composite. Several multilayer, multifunctional coating systems are proposed.