Abstract
Fatigue crack growth (FCG) rates of mill annealed Alloy 600 in NaCl solution were studied by a fracture mechanics test method. Compact tension (CT) specimens were tested under load control with a sinusoidal wave form, in accordance with ASTM specification E647-83, to investigate the effects of environment, load frequency (f), load ratio (R=Pmin/Pmax). The FCG rates of Alloy 600, R=0.1, f=1Hz, were quite similar in air, distilled water, and NaCl (0.6M, 0.1M, and 0.001M) solution at room temperature. Environmental enhancement effect on the FCG rate of Alloy 600 was not significant in NaCl solution. Variations of the load frequency (0.03Hz-3Hz) did not influence the FCG rates of Alloy 600 significantly in air and 0.0M NaCl solution. The FCG rates of Alloy 600 in air and 0.1M NaCl solution increased with increasing the load ratio. Compared with the corrosion effects, test results showed that the mechanical effects dominated on the FCG rates of Alloy 600 in chloride solution at room temperature. The SEM fractographs showed that significant striations and transgranular fracture modes were observed on tested specimens.