It was recalled that the measurement of relaxation kinetics had identified a so-called activation area. This was the area that was swept out by a dislocation during elementary glide processes. It was shown that all of the methods that had previously been used had ignored a relevant physical quantity. This was the plastic strain-rate at the beginning of the relaxation test. A careful theoretical analysis yielded the interesting result that both the strain-rate sensitivity (or activation area) and the initial plastic strain-rate could be determined unambiguously by using current relaxation tests. The initial plastic strain-rate was thus found to depend markedly upon the plastic deformation which preceded the relaxation test. It was also strongly influenced by the temperature.

Interpretation of the Measurement of Activation Parameters in L12 Alloys. G.Saada, J.Bonneville, P.Spätig: Materials Science and Engineering A, 1997, 234-236, 263-6