<c+a> dislocations and their interactions with other crystal defects in a Mg alloy

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 dislocations, with either a 60° or a screw component, were observed in Mg matrix, and both of them could form low-angle tilt grain boundaries during plastic deformation. dislocations could lead to migration of grain boundaries formed previously by dislocations in deformed Mg matrix. Moving dislocations cut and reacted with basal stacking faults, producing new defect structures during deformation. The mechanisms for interaction/reaction between 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 dislocations with relatively compact cores during plastic deformation, instead of immediate dissociation on basal planes.

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