Abstract:Based on the hot compression tests, the effects of deformation temperature and pre-deformation on the microstructure evolution of a hybrid (TiB+Y₂O₃)/near α-Ti matrix composite were studied. The results indicate that the size of silicide precipitated increases with increasing deformation temperature, but its quantity increases first and then decreases. Pre-deformation makes the precipitation position of silicide transform from α/β interfaces or β blocks to uniform distribution inside the matrix. Dynamic recrystallization (DRX) is the main reason for grain refinement of composite, and the dislocations produced by pre-deformation accelerate the process of continuous dynamic recrystallization (CDRX). During the deformation process, dislocations proliferate and aggregate around the broken TiB_w and polymerized Y₂O₃ reinforcements, which promotes the refinement of local grains. Different from the effect of TiB_w and Y₂O₃ on the grain refinement, nano silicides promote the DRX of α grains by pinning grain boundaries and blocking the movement of dislocations according to their different distribution positions.

Key words: near α-Ti matrix composite; microstructure evolution; silicide precipitation; dynamic recrystallization; hot compression deformation