Transition behaviour of deformation mode from shearing to looping in an Al-Li-Ag ternary single crystal

Abstract

The transition behaviour of the deformation mode from shearing to Orowan looping has been investigated in ternary Al- approximate to 2.0 wt% Li-0.4 wt% Ag single crystals using transmission electron microscopy. The critical loop size corresponding to the critical planar particle size for the transition and the dislocation pair spacing are distinctively small compared with those in an Al-Li binary single crystal. The antiphase-boundary energy of the delta' phase is thus estimated to be distinctively large (about 0.123 J m(-2)) compared with the binary crystal (about 0.100 J m(-2)). The significant enhancement of the antiphase-boundary energy of the delta' phase in an Ag-containing crystal is believed to be due to a strong enrichment of the delta' phase with Ag.