1983 Volume 32 Issue 355 Pages 441-445
Sustained load tests were performed on a sensitized high-strength aluminum alloy with repetitional stresses of small amplitude and of constant low strain rate superimposed in 3.5% NaCl solution. The crack growth rate of stress corrosion cracking (SCC) remarkably accelerated under repetitional stresses of a high strain rate K (dynamic SCC), whilst SCC crack growth rate greately decreased under repetitional stresses of a low K owing to the dissolution-induced crack tip blunting. SCC crack growth rate varied much even under a constant K condition. Especially da/dt varied surprisingly under repetitional stresses of a low strain rate K, which may be explained by such a process competition model that one of the processes of fatigue crack growth by repetitional stresses, dissolution-induced crack tip blunting and SCC crack growth by a damage of passive films occurs exclusively.