Effect of heat treatment on microstructure and tensile properties of 2 vol.% TiCp/near-β Ti composite processed by isothermal multidirectional forging

Abstract

In this work, effect of heat treatment on microstructure and tensile properties of 2 vol%TiCp/near-β Ti composite processed by isothermal multidirectional forging was investigated. The microstructure observation shows that multi-directional α/β forged composite owns large number of substructures within β grains that present strong texture {100}. After the solution treatment, TiCp and adjacent β grain respect the burgers orientation relationship {111}TiC//{111}β, and there are still some substructures within the β matrix. Same as other alloys, aging temperature has significant effects on the morphology and distribution of needle-like secondary α phase. Owing to the addition of TiCp, the more and refined secondary α phase are precipitated by compared with matrix alloy. The results of the tensile tests show that isothermal multidirectional forged composite possess a reliable strength (~990.6 MPa) and elongation (~10.2%). The elongation of composite is improved by solution treatment, which was attributed to the tailoring of β matrix. After aging treatment, the composite owns the high strength (~1555.7 MPa) and reliable ductility (~2.7%) because of the precipitation of various α phases.