Slip in single crystals of mercury

Abstract

Slip modes in single crystals of mercury deformed in tension at −70°c and at −183°c were determined experimentally, using conventional techniques of slip line observation and x-ray diffraction. At both temperatures the slip plane was , where indices are given with respect to the facecentred rhombohedral cell. At −70°c some crystals slipped in the direction and the remainder in the direction. For both these modes the mean critical resolved shear stress was 16±5 g mm⁻². At −183°c some crystals slipped in the direction with a critical resolved shear stress of 50±17 g mm⁻²; the remainder, which in the light of the behaviour at −70°c would have been expected to slip in , deformed by twinning without prior slip. The interatomic spacing along is 15% greater than that along , the closest-packed direction; the predominance of as a slip direction is therefore surprising.