The basal slip in zinc under static and dynamic loading

Abstract

This paper presents the results of an investigation of static and dynamic shear behaviour of two purities of zinc single crystals. All the crystals tested were in the form of cylindrical rods with the [0001] crystallographic direction parallel to the rod axis. The static tests were performed by applying simple transverse shear loading in one of the slip directions to one end of the crystals with the other end of the crystals rigidly clamped. The static shear stress vs. shear strain relations are obtained from these tests. The dynamic tests were conducted by suddenly stopping (within a period of about 25 × 10^(−6) sec) one end of the crystals which were moving in the slip direction with various velocities. The resulting waves of plastic shear deformation which propagate from the stopped ends of the crystals toward the free ends are analysed. The analysis is based upon the assumption that elastic strains may be neglected in comparison with the plastic strains. The use of the results of this analysis in conjunction with measurements of the permanent lateral deflections of the crystals resulting from the dynamic tests leads to the determination of dynamic shear stress vs. shear strain relations. The results of this study show that the stress required to produce a given permanent basal shear strain in single crystals of zinc is considerably greater under the dynamic conditions employed than under static conditions. This stress decreases with increasing temperature.

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