The response of polycrystalline α-Zr to various deformation conditions was investigated by using electron back-scattered diffraction methods. The deformation conditions included quasi-static compression and tension at room and cryogenic temperatures; together with Taylor cylinder impact. The resultant data gave the spatial resolution of individual twin-system activity, as a function of the progress of deformation. Over 300
deformation twins were analyzed in order to identify the type of twin system and active variant; together with the Schmid factor of the parent orientation. The data furnished information on the distribution of Schmid factor and variant rank as a function of twin system and deformation conditions. The results revealed significant deviations from a maximum Schmid factor activation criterion, and suggested that deformation twinning was greatly affected by local internal stress heterogeneities and by the sense of the applied stress.

Deformation Twinning in Polycrystalline Zr - Insights from Electron Back-Scattered Diffraction Characterization. J.F.Bingert, T.A.Mason, G.C.Kaschner, P.J.Maudlin, G.T.Gray: Metallurgical and Materials Transactions A, 2002, 32[3A], 955-63