Orientation dependence of deformation twinning in Cu single crystals

Cu single crystals were subjected to dynamic compression plastic deformation to investigate orientation-dependent twinning. The experimental results showed that twinning is closely related to the ratio of the maximum Schmid factor for twinning partial (m(T)) to the maximum Schmid factor for perfect dislocation (m(S)), m(T)/m(S), rather than m(T). The twin volume fraction V-T increases with the m(T)/m(S) value and the most favorable orientation for twinning has the maximum m(T)/m(S) value (1.15). The relationships of m(T)/m(S) with both effective stacking fault energy gamma(eff) and threshold stress for twinning tau(T) were established for understanding orientation-dependent twinning. Further insights into the orientation-dependent twinning and guidance for developing bulk high density nanotwinned materials are provided. (C) 2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.