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

Abstract 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 α in log CPR vs. log SR plots had different values for different SCC morphologies. Intergranular SCC is more steeply accelerated by SR, αIG=0.5–0.7, than transgranular SCC, αTG=0.2–0.3. The differences found between intergranular SCC and transgranular SCC were analysed under the light of the available SCC mechanisms.