The effect of deviation from the Burgers orientation relationship on slip transferability across α/β interfaces in a dual-phase titanium alloy

Most of damage events are attributed to crack initiation induced by the dislocation accumulation at phase boundaries (PBs) in dual-phase titanium alloys, but the slip transferability across PBs that depends on the deviation of the α/β phases from the classic Burgers orientation relationship (BOR) still remains unclear. In this work, we investigated the interaction of dislocations with PBs in a dual-phase Ti–Al–Mo–Cr–Fe alloy. The Burgers misorientation angle (BMA) is introduced to describe the deviation of the two phases from the BOR (non-BOR). The experimental results show that prismatic < a > in α phase favorably transmits into {110} < 111 > dislocations in β at PBs with high BMAs, i.e., P_α → {110}_β. However, the P_α → {112}_β and basal < a > _α → {110}_β mainly concentrated at PBs with low BMAs. The general effect of the BMAs on slip transferability across PBs is explored. Furthermore, the best misorientation angle/axis pair of the BMAs preferable for slip transmission is proposed.