EFFECT OF IODINE ON STRESS CORROSION CRACKING OF N18 ZIRCONIUM ALLOY
碘对N18锆合金应力腐蚀开裂的影响

The effect of iodine partial pressure on the iodine-induced stress corrosion cracking of recrystallized N18 zirconium alloy was investigated.The characteristics of the SCC fractures have been examined by SEM.The results show that the susceptibility of N18 to I-induced SCC increases with the increasing iodine partial pressure,i.e.the critial stress intensity factor K ISCC and stress decrease,as well as critical time shortens with the increasing iodine partial pressure.The speedily propagation of stress corrosion cracks is influenced by iodine partial pressure.The higher the iodine partial pressure is,the lower the stress intensity factor needs to accelerate cracking.The partial pressure of iodine influence not only the formation of corrosion products,but also the mode of cracking.The effect of iodine partial pressure on the SCC of N18 zirconium alloy can be explained by diffusion mechanism and the reaction balance of Zr-I-O system.