Crystal plasticity behavior of single-crystal pure magnesium under plane-strain compression

Abstract

A phenomenological crystal plasticity constitutive model for magnesium single crystal was presented. Four deformation mechanisms (including basal 〈a〉, prismatic 〈a〉, pyramidal 〈c + a〉 slip and tension twin) and their interactions were considered. Twin-induced lattice reorientation was also incorporated in the model. The proposed model was then applied to the simulation of plane-strain compression deformation for different orientations. Related material parameters were calibrated at first according to the classical channel-die tests. The predicted macro-and microscopic responses, along with the experimental results, show strong orientation-dependent properties. It is also found in the simulation that basal slip in the twinned region is active even before the saturation of twin activity in a twin-favored case. Furthermore, the effect of an initial deviation angle on the mechanical responses was evaluated, which is proved to be also orientation-dependent. Basal slip is found to be easily activated due to a slight deviation, while a slight deviation in the twin-favored case could result in a significant difference in the mechanical behavior after the reorientation. The effort on the study of magnesium single crystal in the present work contributes to further polycrystalline analysis.