抄録
The susceptibility to stress corrosion cracking (SCC) and its potential dependence of Zircaloy-2 were investigated. The SCC tests were conducted with CH3OH solutions containing HCl under given potentials at room temperature. The critical potential for SCC in 0.4% HCl solution moved to the negative direction, and the susceptibility to SCC increased. The potential range for SCC corresponded with the active region in the potentiostatic anodic polarization diagram, and the test specimen was attacked by uneven general corrosion when the potential was moved to the positive direction. The fracture mode of SCC differed from that of general corrosion, i.e., the transition of intergranular fracture to cleavage-like fracture was observed in the SCC potential region, whereas only intergranular corrosion was found in the active region. It is, therefore, considered that cleavage-like fracture is caused by mechanical stresses associated with the absorption of hydrogen generated by an intergranular corrosion reaction. A model for cracking was proposed based on these experimental results.
