INTERFACE MICROSTRUCTURES IN TI-BASED COMPOSITES USING TIB2 C-COATED AND UNCOATED SICF AFTER SHORT-TERM THERMAL EXPOSURE/

The extent of interfacial reaction after short-term thermal exposure d uring vacuum plasma spraying (VPS) and vacuum hot-pressing (VHP) of Ti -based metal-matrix composites (MMCs) using TiB2/C-coated and uncoated SiC fibres has been investigated by a combination of scanning and tra nsmission electron microscopies. There is no interfacial reaction afte r short-term thermal exposure during VPS manufacture of SiC(f)/Ti MMCs using either TiB2/C-coated or uncoated SiC(f). There is only limited interfacial reaction after short-term thermal exposure during VHP manu facture of SiC(f)/Ti-6Al-4V MMCs using TiB2/C-coated SiC(f). In the in itial stage of the interfacial reaction, TiB needles are formed by pre ferential nucleation and growth at beta particles and grain boundaries in the Ti-6Al-4V matrix.