Temperature dependency of slip and twinning in plane strain compressed magnesium single crystals

This study aims to characterize the critical resolved shear stresses (CRSSs) of slip and twinning in magnesium crystals, as a function of temperature, under conditions of imposed strains. Several crystal orientations have been deformed by plane strain compression in a channel die from room temperature to 450 degrees C. The deformed microstructure and microtextures are characterized by systematic electron backscatter diffraction orientation maps giving unequivocal primary and secondary twin determinations. In parallel, a crystal plasticity code based on the CRSS and the Schmid law is used to compare model predictions with the active slip and twinning systems and the flow stress. It is shown that tensile twinning and basal slip are only slightly temperature-dependent but that the other systems (compressive twinning, prismatic and pyramidal II (c + a) slip) possess CRSS values which decrease substantially with temperature. (c) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.