Evidence for stable stoichiometric Ti2C at the interface in TiC particulate reinforced Ti alloy composites

Ti-6%Al-4%V composites containing 20 vol.% TiC particles were sintered at t emperatures between 1273 and 1773 K for holding times of up to 20 h. Neutro n diffraction and low voltage field emission gun scanning electron microsco py were used to investigate the development of the interfacial reaction reg ion between the reinforcement and matrix. It has been observed that there i s an interaction zone surrounding each particle caused by the diffusion of carbon from the reinforcement to the titanium alloy matrix. The extent of t his reaction increases with increasing processing temperature and holding t ime. The single phase formed at the interfacial boundary between the partic les and the matrix was determined from lattice parameter measurements to be stoichiometric Ti2C. The significance of these findings are discussed in t erms of previous work on interfacial characterization of TiC particulate re inforced Ti-6%Al-4%V composites. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved.