Evolution of microstructure and mechanical properties during short-time annealing of a hard-plate rolled 2 vol% TiCp/near-β titanium matrix composite

Abstract

In this study, to suppress the edge cracks and efficiently improve the mechanical properties, hard-plate rolling and subsequent short-time annealing were conducted on the 2 vol% TiCp/near-β titanium matrix composites, and the effects on the microstructure and mechanical properties were investigated systematically. The results show that the TiCp are arranged along the rolling direction, some primary α phases are elongated into fiber-like, and β grain boundaries are not visible. The static recrystallization and recrystallization textures are developed after a short time of annealing in the β phase region of the hard-plate rolled plates. After annealing, the α phases disappear, the new β recrystallized grains replace the deformed ones, and the texture strength of γ fiber ({111}<112> component) is enhanced. The ductility of hard-plate rolled plates increases while the strength decreases after annealing, but the ductility starts to decrease with the completion of recrystallization and grain growth. After annealing at 860 °C for 1 min, the average size of β grain is about 9.8 μm and the properties of the samples are better optimized than those after hard-plate rolling. The ultimate tensile strength decreases from 1564 MPa to 1337 MPa, and the elongation increases from 2.8% to 7.8%. The application of hard-plate rolling and short-time annealing processes can refine grain effectively and improve the properties of plates.