INTERFACE CONTROL AND DESIGN FOR SIC FIBER-REINFORCED TITANIUM ALUMINIDE COMPOSITES

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