Microstructure and Mechanical Properties of In-situ Synthesized (TiB+TiC)/Ti-8Al-1Mo-1V Composites

Ti-8Al-1Mo-1V matrix composites (TMCs) reinforced with TiB and TiC which molar ratio was 1∶1 were synthesized by a consumable arc-melting technology utilizing the reactions of Ti with C and B4C.The phase constituents were identified by X-ray diffraction (XRD) and microstructure was observed with optical microscopy (OM) and scanning electron microscopy (SEM).The effects of reinforcements on the mechanical properties at room temperature were discussed.The results show that the distribution of reinforcements in the composite was homogeneous.TiB exhibited a chopped fiber-like shape and TiC was equioxed.For the composite with 10vol.% reinforcements,the yield strength,ultimate tensile strength and elastic modulus increased while the ductility decreased.For the composite with 20vol.% reinforcements,elastic modulus increased significantly.However,the ductility decreased sharply and the fracture types turned from plastic fracture to brittle fracture.