Evolution of microstructure and tensile properties of in situ titanium matrix composites with volume fraction of (TiB plus TiC) reinforcements

In this paper, high temperature titanium matrix composites with different volume fraction of (TiB+TiC) reinforcements were in situ synthesized by casting route. The microstructure and tensile properties of the composites were presented and discussed. The results reveal that both the TiB whiskers and TiC particles tend to segregate at prior beta boundaries. The prior beta grain size and alpha lath width are gradually refined with increasing volume fraction of reinforcements. Evolution of tensile properties shows that enhancement in yield strength and ultimate tensile strength with addition of reinforcements is primarily attributed to microstructural refinement, while the remarkable reduction in ductility is possibly due to the cracking of TiB whiskers and TiC particles. (C) 2012 Elsevier B.V. All rights reserved.