Microstructure evolution and tensile properties of as-rolled Ti-Mo-Si composite

Abstract

There is a keen interest in developing discontinuously reinforced titanium matrix composites (DRTMCs) as lightweight structural materials for aerospace and automotive industries. However, a long-standing problem for these materials is the conflict between strength and ductility. To address this challenge, a novel Ti-Mo-Si composite with network microstructure is successfully fabricated by spark plasma sintering and hot rolled in the β region (900 °C) with different statin rate. We find that a thickness reduction of 20% is optimal for improving the strengthening efficiency and corresponding ductility. However, with the reduction of thickness in the hot rolling process, the strength increases while the ductility decreases, which is mainly because of the spheriodiation of α-Ti and reinforcements, as well as the strengthening of the interface between reinforcement and matrix. In addition, the composite after hot rolling follows fractured reinforcement and dimple mechanisms at small thickness reduction, while it obeys a quasi-cleavage fracture mechanism with significant thickness reduction.