Variant selection criterion for twin variants in titanium alloys deformed by rolling

A new selection criterion to explain the activation of the twinning variant is proposed based on the calculation of the deformation energy to create a primary twin. The calculation takes into account the effect of the grain size using a Hall–Petch-type relation. This criterion allows very good prediction for the variant selection to be obtained. The calculations are compared with the experimental results obtained on T40 deformed by rolling.