Ultrafine processing of (TiB+TiC)/TC18 composites processed by ECAP via Bc route

Equal channel angular pressing provides a convenient approach to introduce ultrafine grain size into commonly used metallic materials. In this study, equal channel angular pressing of (TiB+TiC)/TC18 composite was carried out under different passes via route Bc. Microstructure evolution is systematically investigated by optical microscope (OM), scanning electron microscope (SEM), and transmission electron microscope (TEM). The results show that grain boundary sliding contributes much to the plastic deformation and grains are refined largely to 100 nm for (TiB+TiC)/TC18 with 0.2% B4C addition after two passes. The appearance of dislocation accelerates the transformation of spherical α recrystallized grains. Sufficient recrystallization is obtained after three passes. Tensile tests show that both high strength and elongation appear in the specimen with 0.2 wt% B4C addition, which is deformed repeatedly after three passes. Equal channel angular pressing thus be a viable mode for producing titanium matrix composite with both high strength and ductibility.