Strength and ductility of some monomorphous HCP metals

Abstract

The effects of temperature, strain rate, and stress on the mechanical properties of Lu, Cd, and Zn were studied. Metals with a hcp lattice, in contrast to metals with a cubic lattice, ordinarily undergo considerably less plastic deformation, since easy slip occurs only in the basal plane at ordinary temperatures. Because of the limited capacity for plastic deformation by slip in hcp metals, the capacity for deformation by means of twinning is evidently highly developed. The ductility of hcp metals increases sharply on heating. It is possible that deformation occurs not only by means of slip but also by other mechanisms (diffusion, rotation of blocks, etc.). In any case, the ductility of zinc and cadmium at high temperatures is the same as that of metals with a cubic lattice. The strength and ductile characteristics of these metals as a function of temperature is often nonmonotonic in character, with dips of the strength and ductility. At temperatures below 0/sup 0/C the ductility of these metals is low and they tend to be brittle. As follows from the results, hcp metals can be subjected to plastic deformation in a broad temperature range without danger of cracks or fracture under conditions in whichmore » the compressive components of stress are employed, i.e., under mild deformation conditions (compression, pressing, rolling, etc.).« less