ON SEQUENCES OF ALTERNATE STABLE AND UNSTABLE REGIONS ALONG TENSILE DEFORMATION CURVES

The occurrence and boundaries of (in-)stabilities along stress strain curves are investigated for f.c.c. solid solutions of CuMn. There are up to four temperature intervals where the sigma(epsilon)-curves over their whole extension are either smooth (stable deformation) or serrated (unstable deformation). In between, three transitional intervals, named alpha, beta, and gamma, are constituted. Here two or more regions of stable and unstable deformation alternate along sigma(epsilon). In particular, inside interval-beta a region of stability is embedded between two regions of instability. For two Mn concentrations the variation of the boundaries with temperature and strain rate is investigated for the intervals-alpha and beta. The results allow a comparison with theoretical "scenarios" developed by Kubin and Estrin. Possibilities for an improvement and/or extension of this model are discussed.