{332}⟨113⟩ Twinning transfer behavior and its effect on the twin shape in a beta-type Ti-23.1Nb-2.0Zr-1.0O alloy

The interaction between twins and grain boundaries (GB) has an important influence on the deformation and fracture behavior of materials. In the present work, {332}<113> twinning transfer (TT) behavior and its effect on the twin shape in a deformed beta-type Ti-23.1Nb-2.0Zr-1.0O Ti alloy were investigated experimentally and with molecular dynamics simulation. The crystallographic alignment factor of the two twinning systems in the neighboring grains and the misorientation angle of the grain pairs were found to influence the occurrence of TT. This further determines the twin shape: twins present a ruler shape when TT occurs but are in a lenticular shape otherwise. Such different twin shapes are attributed to the local stress states related to TT occurring or not. Both ruler-shaped paired twinning and lenticular twinning would provide effective mechanisms to release or reduce the stress concentration in front of the twin tips in different grain pairs. (C) 2021 Published by Elsevier Ltd on behalf of Chinese Society for Metals.