Kink formation and concomitant twin nucleation in Mg–Y

Abstract

During in situ tensile loading of a Mg–2.5 wt%Y alloy, a large kink band was observed. The orientation of the kink band varies continuously with a maximum misorientation angle of 18° with respect to the matrix grain. The formation of the kink band is accompanied by the nucleation of numerous {101¯2} twins at the kink boundaries. A mechanistic model is proposed to account for this unique kink band and concomitant twin nucleation via dissociation of basal dislocations. This mechanism is aided by the presence of Y, which suppresses {101¯2}twinning and simultaneously decreases the stacking fault energy.