Grain Boundary Character Distribution of TLM Titanium Alloy During Deformation

The grain boundary character distribution of TLM titanium alloy (with a nominal chemical composition of Ti-3Zr-2Sn-3Mo-25Nb) was studied under the deformation condition with different strain rates and compression reductions. The experimental results showed that the evolution and character distribution of grain boundaries structure during deformation were both related to grain boundary coupling, sliding, migration, and the grain rotating in nature. In TLM titanium alloy, the type of grain boundaries under different deformation condition included high-angle boundaries, low-angle boundaries, and the CSL boundaries of Σ3, Σ13, Σ29, and Σ39. Under the strain rate of 1 s^?1, the numbers of grain boundaries with misorientation angle of 3°, 30°, and 60° all decreased obviously with the increasing compression reduction to 4.5%, comparing to those obtained under the strain rate of 0.001 s^?1. Under the strain rate of 1 s^?1, the numbers of Σ29 boundaries greatly increased with the compression reductions of 3 to 4.5% comparing to those obtained under the strain rate of 0.001 s^?1, and the numbers of Σ3 boundaries increased firstly and then stabilized with the compression reduction increasing from 0 to 4%, while the numbers of Σ39 boundaries decreased with the compression reduction increasing to 4.5%.