Abstract
<c+a> dislocations and their interactions with other crystal defects in a Mg alloy have been investigated using atomic-resolution aberration-corrected scanning transmission electron microscopy. Two types of <c+a> dislocations, with either a 60° or a screw <a> component, were observed in Mg matrix, and both of them could form low-angle tilt grain boundaries during plastic deformation. <c+a> dislocations could lead to migration of grain boundaries formed previously by <a> dislocations in deformed Mg matrix. Moving <c+a> dislocations cut and reacted with basal stacking faults, producing new defect structures during deformation. The mechanisms for interaction/reaction between <c+a> dislocations and other defects are modeled based on atomic-resolution observations. These experimental results provide clear evidence for the occurrence of long range motion of <c+a> dislocations with relatively compact cores during plastic deformation, instead of immediate dissociation on basal planes.
Published Version
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