It was recalled that the <011> type-II twin was a major twinning mode in NiTi shape memory alloys. Its response to applied stresses was responsible for various inelastic deformation processes. In order to predict shape recovery characteristic under various conditions, it was important to predict the martensite de-twinning characteristic before reverse transformation. However, due to its irrational nature, the type-II twin plane was not as easily analyzed as that of other types of twin and controversy existed over the nature of the twin boundary. The <011> type-II twin boundary, before and after deformation, was investigated here. A complete model of the <011> type-II twin plane, and its role in de-twinning, was proposed and could be used to account for various experimental observations.

Twinning and Detwinning of <011> Type II Twin in Shape Memory Alloy. Y.Liu, Z.L.Xie: Acta Materialia, 2003, 51[18], 5529-5543