Activating profuse pyramidal slips in magnesium alloys via raising strain rate to dynamic level

Pyramidal slip is critically important for ductility improvement of Mg alloys since it is the exclusively remained mode to accommodate strain along c-axis of alpha-Mg matrix during the later stage of deformation. The routes of promoting pyramidal slips are still limited. In this letter, we raise the tensile strain rate to dynamic level of 2000/s and effectively enhance both pyramidal and basal types dislocation activities in Mg-Sn binary alloys. The pyramidal dislocation activities could be rationalized by the critical resolved shear stress variations with strain rates. The enhanced density of both < c+a > and < a > dislocations lead to the positive strain-rate sensitivity of ultimate tensile strength and elongation. (C) 2016 Elsevier B.V. All rights reserved.