Stage-III hardening revisited

The influence of stress-concentration assisted cross slip of screw dislocations on the hardening behaviour of face-centred cubic (fcc) single crystals is studied. The theoretical framework developed does not rely on specific assumptions concerning the geometrical arrangement of dislocations nor the cross-slip mechanism. Relations are derived that allow for characterizing the hardening behaviour after the onset of Stage III in terms of the Stage-II hardening coefficient and of the critical stress at which abundant cross slip becomes possible. A detailed comparison of the theoretical results with experimental findings demonstrates that the theory gives a good description of the observed hardening behaviour of fee metals in the early Stage-III regime.