Deformation twinning in face-centred cubic metals

Abstract The principal features of the experimental results of Blewitt et al. (1957) and of Suzuki and Barrett (1958) on deformation twinning in face-centred cubic metals are explained in terms of an extension of the ‘prismatic’ source mechanism of Cottrell and Bilby (1951). Suitable prismatic dislocation sources are thought to be long jogs in the dislocations of the two conjugate slip systems in a work-hardened metal and prismatic dislocation loops produced by vacancy condensation in a neutron-irradiated metal. The dissociation of slip dislocations is also considered and is found to be an unlikely mechanism for the production of deformation twins in copper, silver or gold.