The different effects of solute segregation at twin boundaries on mechanical behaviors of twinning and detwinning

In the present study, a comparative study about the hardening effect of solute segregation at {101¯2} twin boundaries (TBs) on a {101¯2} twinning predominant deformation and a detwinning predominant one was carried out. The influence of the pre-straining and subsequent annealing conditions on mechanical behavior was systematically addressed. Our results show that solute segregation at TBs can occur even at 100 °C. The annealing at 100 °C for 20 min induces a partial segregation at TBs, while that at 150 °C or higher temperature for 20 min can induce a complete solute segregation. The annealing conditions and pre-strain levels generate quite different effects on deformation by twinning and that by detwinning. Both annealing hardening and annealing softening might happen during the twinning predominant recompression. Annealing hardening occurs only with pre-strains of 3.0% and 5.5% after annealing at 100 °C for 6 h. A higher pre-strain or a higher annealing temperature or a longer annealing time generate a higher annealing softening effect. However, during the detwinning predominant recompression, all used annealing treatments generate hardening effect in all the pre-strained samples. With a complete solute segregation at TBs, a hardening of about 11-25 MPa is generally achieved. It is also found that solute segregation at TBs reduces the strain hardening rate of deformation by TBs migration.