Prismatic dislocation loop rotation and self-climb phenomena in Al—0.13 wt. % Mg

Direct experimental evidence is presented of the rotation of hexagonal prismatic dislocation loops in a quenched aluminium-magnesium alloy. The hexagonal prismatic loops, which are produced by the unfaulting of Frank vacancy loops, are shown to undergo rotation about an axis parallel to their pure-edge sides, from their original {111} orientation to an orientation close to {110}. In no observed instance has the precise {110} orientation been adopted. It is also shown that hexagonal prismatic loops in the {111} orientation may develop 〈112〉 type sides by self-climb, and that these loops also are capable of rotation. The assertion that hexagonal prismatic loops need to lose their pure-edge sides and adopt a rhombic shape on the {111} plane, prior to a possible orientation change, is thus disproved.