1994 年 43 巻 488 号 p. 551-555
The susceptibility to intergranular corrosion and stress corrosion cracking (SCC) of cold-rolled Zircaloy-2 in CH3OH/0.4%HCl solution at room temperature was examined fractographically.
It was found from the stress-free exposure tests that the weight loss due to intergranular corrosion increased gradually with exposure time. From the subsequent tensile tests in air, the mechanical properties deteriorated greatly though there was less dependent on rolling reduction. The resulting appearance consisted of intergranular and ductile fracture and their area fractions were approximately constant, independently of rolling reduction. The threshold stress to SCC occurrence did not exist essentially, and its potential range corresponded with the active region of anodic polarization diagram. However, the uneven general corrosion appeared when the potential was moved to the positive direction. The fracture mode was changed from an intergranular into a cleavage-like fracture. Here, the former area fraction decreased with an increasing rolling reduction and the latter inversely increased.