The I-SCC behavior of N18 alloy at constant strain rate

To evaluate ISCC behaviors of as-received and re-fabricated N18 alloy sheets, the tensile tests were conducted at the constant strain rate in the different medium including air, ethanol, and iodine ethanol at room temperature and the iodine vapor at 350°C and 400°C. The effects of iodine concentration, strain rate, alloy composition and texture on I-SCC behavior of zirconium alloys were investigated. The results indicate that N18 alloy would become more susceptible to SCC as iodine concentration increase and stain rate decrease or re-fabrication, and SCC sensibility of N18 alloy would be influenced not by iodine pressure but temperature in iodine vapor. The chemical composition difference between N18 and zircaloy-4 would hardly affect SCC behavior, but the texture would have strong influence on SCC for N18 alloy although there is a little difference between transverse direction (TD) and rolling direction (RD) specimens. The stress corrosion initiation mechanism must therefore be analyzed as a corrosion-strain interaction linked to the chemical effects and mechanical effects.