1. Shenyang Aircraft Industry (Group) Co. , Ltd. , Shenyang 110850, China
2. School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China
3. Shi-Changxu Innovation Center for Advanced Materials, Institute of Metal Research,Chinese Academy of Sciences, Shenyang 110016, China
The near β high-strength titanium alloy is widely used in the aerospace field. Microstructure control is being focused on to achieve a good match between strength and toughness of high-strength titanium alloys. The size of β grains and the morphology of grain boundaries of a novel near β titanium with different heat treatments were characterized in this paper.The grain size was affected by the solution time, and the behavior of grain boundary coarsening was affected by (α+β) phase region solution. The effect of grain size and the morphology of grain boundary on mechanical properties were studied. The
results show that the β grains grow up gradually with the extension of solution time in β phase region, and the size of β grains has no significant effect on tensile property and impact toughness. In the process of two-stage solution, the primary α phase precipitates preferentially along the grain boundary, which coarsen the grain boundary. The lower temperature in the (α+β) phase region solution, the more obvious the grain boundary coarsening. The grain boundary coarsening reduces the strength and plasticity of at the same time, but has no significant effect on the impact toughness.