Anomalous temperature dependence of the yield stress by {1122}〈1123〉secondary pyramidal slip in cadmium crystals—I. Experiments

Abstract

Yield stress σ_y due to {1122}〈1123〉slip (SPCS) in cadmium crystals is proportional to temperature T (anomalous temperature dependence). An increment of strain rate causes σ_y to increase. The deformation proceeds inhomogeneously with the nucleation and growth of bundles of slip steps (BSS) which correspond to etch pit bands (EPB). The strain ϵB in BSS or EPB is constant independent of applied strain. The density of dislocations in EPB is nearly constant independent of strain, strain rate and T. ϵ_B and the mean free path of edge dislocations decrease exponentially with increasing T. The above results suggest that the deformation mode by SPCS is similar to Lüders deformation and the growth rate of BSS or EPB width increases with increasing T and strain rate. The anomalous temperature dependence is interpreted by the immobilization of edge dislocations and the growth rate related with double cross slip.

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