On the mechanisms of work hardening and flow-stress saturation

The mechanical-threshold-strength (MTS) work hardening model is based on the separation of the constant-structure part of the strain rate sensitivity from the structural evolution part. These are fundamentally different processes and require different theoretical models. The MTS model differ from the multi-parameter-microstructural (MPM) model in three principal ways: in the microstructural description; in the handling of the kinetics part; and in the treatment of the structural evolution part of the problem. A useful background for the comparison of the two approaches is the results of the examination of the variation in the saturation stress, τs, with temperature and strain rate for four different face-centered cubic metals: Al, Cu, Ni and Ag.