THE CRITICAL CONDITIONS FOR JERKY FLOW - DISCUSSION AND APPLICATION TO CU/MN SOLID-SOLUTIONS

The transitions between smooth and jerky flow have recently attracted a significant interest. Considerations of critical strains and stresses for the onset or disappearance of jerky flow are presented in this paper aiming at explaining some recent observations by Kalk and Schwink on CuMn solid solutions. Three particular intervals of temperature, labelled alpha, beta, and gamma, are examined, which correspond to different patterns of behaviour of the critical strains. It is shown that the experimental observations at the lowest temperatures (interval-alpha) are understood reasonably well. An explanation is proposed for the occurrence of an island of stability in the interval-beta which exploits the thermally activated nature of recovery processes. The particular type of behaviour observed at higher temperatures (interval-gamma) does not seem to be completely interpretable in terms of the current models.