Slip dislocation and twin nucleation mechanisms in hcp metals

A new nucleation mechanism is proposed for $$ \{ 10\bar{1}1\} $$ deformation twin in hcp materials. The mechanism is based on the results of atomistic computer simulations. It was found that under high shear stress applied on $$ \{ 10\bar{1}1\} $$ plane (the stress level is about 7 % of shear modulus), the core of a slip dislocation can transform to a twin embryo. The transformation and subsequent twin growth are accompanied by nucleation and migration of interfacial defects including disconnections and stacking faults. The paper provides the analysis of the nature of these defects and describes the reactions between them.