Several mechanisms have been proposed to explain the intergranular stress corrosion cracking (IGSCC) of Alloy 600 in BWR, but slip-dissolution at grain boundaries remains the most recognized cause. However, it is still uncertain whether the above degradation is accompanied by selective internal oxidation (SIO) as a precursor. Following new insights into the creviced bent beam (CBB) test, relevant evidence was discovered. Additionally, the results of First Principle Calculation indicate interstitial O actively competes for chromium in IG carbides to form chromium oxides during the SIO process, instead of passively waiting for the oxidation/decomposition of carbides to provide a chromium source.

中文翻译：

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沸水堆（BWR）环境中合金600应力腐蚀开裂机理的新见解

人们提出了几种机制来解释沸水堆中合金 600 的晶间应力腐蚀开裂 (IGSCC)，但晶界处的滑移溶解仍然是最公认的原因。然而，目前尚不确定上述降解是否伴随选择性内氧化（SIO）作为前体。随着对裂缝弯曲梁（CBB）测试的新见解，发现了相关证据。此外，第一原理计算的结果表明，间隙O在SIO过程中主动竞争IG碳化物中的铬形成铬氧化物，而不是被动等待碳化物的氧化/分解来提供铬源。