Evidence for an early softening behavior in pure copper processed by high-pressure torsion

摘要

Pure copper of 99.99 purity was processed by high-pressure torsion under a pressure of 6.0 GPa at room temperature through various numbers of turns from 1/4 to 10. Microhardness measurements show that the hardness initially increases to a maximum value at a strain of similar to 5.6, decreases to a strain of similar to 8.4, and then increases slowly to a saturation condition at strains at and above similar to 80. These data are interpreted in terms of the advent of dynamic recrystallization. The results have similarities and differences to the softening with recovery that is well established in high-purity aluminum.