Creep and stress relaxation of germanium single crystals

Isothermal creep and stress relaxation were studied in germanium single crystals oriented for double slip at 400 to 700? C under compressive stresses of 180 to 490 kgf cm^?2. The curves, S-shaped in both types of experiment, were compared with correspondingones derived from a stochastic model involving a spectrum of energy barriers to dislocation movement. Agreement was satisfactory for stress relaxation; discrepancies in the case of creep point to the difficulty of correlating creep and stress relaxation when an equation of state is inadequate as an approximation for representing the plastic response. Differences between predicted and observed behaviour are, however, of diagnostic value concerning the extent of dislocation multiplication and other structural changes.