Twinning system selection in a metastable β-titanium alloy by Schmid factor analysis

Electron backscattering diffraction and Schmid factor analysis were used to study the twinning variant selection in a Ti–25Ta–24Nb (mass%) metastable β-titanium alloy. The two twinning systems {1 1 2}〈1 1 1〉 and {3 3 2}〈1 1 3〉 were observed. For each system the Schmid factor was shown to be a relevant parameter to determine the activated variant. Moreover, selection between the two twinning systems depends on the crystallographic orientation of the grain with respect to the tensile direction.

► A metastable beta Ti-25Ta-24Nb alloy was synthesized by cold crucible semi-leviation melting.
► Electron backscattering diffraction was used to characterize the deformation mechanisms. 2 twinning systems have been identified.
► The Schmid factor was used to determine the activated variant.