New stages in stress—strain curves of germanium at high temperatures

The stress—strain curves of germanium show, besides the well-known stages I—III, a second stage of linear hardening (stage IV) and a second recovery stage (stage V). These new stages have been found in dynamic compression at high temperatures. According to slip-line observations, the main slip system remains dominant up to stage V. The slope of stage IV is independent of temperature and only slightly dependent, if at all, on strain rate. If, for the beginning of stage V, a recovery rate [adot]c, is defined in the same way as in stage III in previous work, [adot]c as a function of temperature and stress is found to fit well with current models that describe jog-dragging of screw dislocations or climb of edge dislocations out of pile-ups.