Deformation twinning in the full-α″ martensitic Ti–25Ta–20Nb shape memory alloy

Abstract Deformation twinning of the Ti–25Ta–20Nb (mass%) shape memory alloy is characterized using EBSD and TEM. The selfaccommodating α″ microstructure is shown to be first deformed using {111} α ″ type I and α ″ type II reorientation twinning. Plastic deformation occurs further by plastic twinning with a new {130} α ″ twinning system. Maximum lattice deformation calculation is a relevant parameter to predict the variant of martensite that is favored during the reorientation process. Conversely, Schmid factor analysis can be used to predict the selection of {130} α ″ twinning variants during deformation. Analogy between {130} α ″ and {332} β twinning systems is highlighted.