Microstructural characteristics and mechanical properties of in situ synthesized (TiB+TiC)/TC18 composites

Trace reinforcements can significantly refine microstructure and improve mechanical performance of composite. In this work, the in situ synthesized Ti-5Al-5Mo-5V-1Fe-1Cr titanium matrix composite containing trace TiB and TiC is fabricated. The microstructural characteristics and tensile properties of the heat-treated materials are investigated, with particular emphasis on researching the spheroidization of α phase and the effects of trace reinforcements. It is revealed that it presents the division of α grain during spheroidization process. The separated α phase, near equiaxed α phase and short-rod α phase tend to be spheroidized during the processing of diffusion. The trace reinforcements can accelerate the spheroidization of α by accelerating the extent of diffusion and then the microstructural homogeneity is promoted. The composite manifests excellent comprehensive mechanical properties due to the microstructural improvement and the effect of the trace reinforcements. © 2011 Elsevier B.V.