Thermal Recovery and Stress-Strain Relation of Polycrystalline Zinc

Abstract

Thermal recovery and its effects on the stress-strain relations of polycrystalline zinc have been investigated experimentally. Specimens were prestrained in compression at a certain temperature and under several constant strain rates, and annealed isothermally. Results obtained are summarized as follows. (1) During both the static and the dynamic deformations at -195°C, no detectable thermal recovery occurs. (2) At -195°C, the stress-strain relation is able to be determined only by the strain rate at the time within the strain rate range of 10^-4/s to 10^-2 and does not depend upon the strain rate history. (3) The activation energy obtained for thermal recovery is about (10∼12)kcal/mol and this value corresponds to the migration energy of vacancies produced during the plastic deformation.