Hot deformation temperature and pre-deformation effect on silicide precipitation behavior of (TiB+Y2O3)/near α-Ti matrix composite
(1. College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China;
2. Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment, Ministry of Education, Taiyuan 030024, China;
3. Kocel Machinery Co., Ltd., Yinchuan 750021, China;
4. Department of Chemical and Materials Engineering, University of Auckland, New Zealand)
2. Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment, Ministry of Education, Taiyuan 030024, China;
3. Kocel Machinery Co., Ltd., Yinchuan 750021, China;
4. Department of Chemical and Materials Engineering, University of Auckland, New Zealand)
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 TiBw and polymerized Y2O3 reinforcements, which promotes the refinement of local grains. Different from the effect of TiBw 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