Effect of the strain rate on stress corrosion crack velocities in face-centred cubic alloys. A mechanistic interpretation

Constant extension rate tests on smooth samples, with strain rate (SR) values from 10(-6) s(-1) up to 20 s(-1) were used to study stress corrosion cracking (SCC) systems in face-centred cubic alloys. It was found that by increasing the SR a monotonic increase of the log CPR (crack propagation rate) takes place. It was also observed that the slope a in log CPR vs. log SR plots had different values for different SCC morphologies. Intergranular SCC is more steeply accelerated by SR, alpha(IG) = 0.5-0.7, than transgranular SCC, alpha(TG) = 0.2-0.3. The differences found between intergranular SCC and transgranular SCC were analysed under the light of the available SCC mechanisms. (C) 2003 Elsevier Ltd. All rights reserved.