Two sorts of repeated transient test (relaxation, creep) were shown to be ideal techniques for the characterization of plastic deformation processes. They yielded similar information concerning microscopic activation volumes; which were the signatures of various operating dislocation mobility mechanisms. Microstructural parameters were also obtained whose values were different during creep and stress relaxation. They characterized work-hardening during the transient and dislocation exhaustion rates, respectively. Experimental results on Ni3Al polycrystals illustrated the possibilities of both tests. In particular, crystals which work-hardened exhibited high dislocation exhaustion rates, as shown by comparing Ni3Al with TiAl, Ge and Cu. The respective contributions to the strain-rate, of mobile dislocation densities and velocities, could also be estimated.

Characterization of Thermally Activated Dislocation Mechanisms using Transient Tests. Martin, J.L., Piccolo, B.L., Kruml, T., Bonneville, J.: Materials Science and Engineering A, 2002, 322[1-2], 118-125