【摘要】 研究了再结晶退火N18锆合金在碘气氛中的应力腐蚀开裂 (SCC)行为 ,着重研究了 35 0℃时碘分压对该合金SCC的影响 .结果表明 ,随着碘分压增加 ,N18合金对碘致应力腐蚀开裂的敏感性增加 ,开裂的临界应力强度因子KISCC降低 ,裂纹萌生所需的应力降低 ,裂纹萌生所需的时间也缩短 ;SCC裂纹的快速扩展也受碘分压的强烈影响 ,碘分压越高 ,裂纹扩展过渡到快速的穿晶准解理方式时对应的应力强度因子越低 ;碘分压不仅影响腐蚀产物层的形成 ,也影响裂纹扩展方式 .碘分压的影响规律可用碘的扩散机制及Zr-I -O体系的化学平衡来解释更多还原

【Abstract】 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.更多还原