Prism stacking faults observed contiguous to a {10-12} twin in a Mg–Y alloy

Using transmission electron microscopy, we document, for the first time, the presence of stacking faults on the (10-10) prism planes in a fine-grained Mg–Y alloy. These prism stacking faults were found to be exclusively contiguous to a {10-12} deformation twin. In addition, the {10-12} twin contained a high density of basal plane stacking faults. Arguments are developed for the interrelationship between the stacking faults on the prism planes in the matrix and those on the basal planes in the twin.