Abstract Solution-annealed Alloy 600 samples were tested under active load conditions in a superheated low pressure H2-steam environment over a range of oxidising potentials relevant to Primary Water Stress Corrosion Cracking (PWSCC). Increased SCC susceptibility was observed for potentials the more reducing than the Ni/NiO transition where a deeper Preferential Intergranular Oxidation (PIO) occurred. Advanced microstructural analysis clearly showed that SCC initiated along the grain boundaries that exhibited Diffusion-Induced Grain Boundary Migration (DIGM), as well as enrichments in Al and Ti. Rather than the result of a single dominant mechanism, the initiation of SCC in Ni-base alloys involves the synergistic interactions between DIGM and the formation of Al- and Ti-enriched oxides, promoting PIO that can fracture with applied stress.

中文翻译：

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600合金加氢蒸汽中晶界迁移与应力腐蚀开裂的相关性

摘要 在与初级水应力腐蚀开裂 (PWSCC) 相关的氧化电位范围内，在过热低压 H2 蒸汽环境中，在主动负载条件下对固溶退火合金 600 样品进行了测试。观察到电位的 SCC 敏感性增加，比发生更深的优先晶间氧化 (PIO) 的 Ni/NiO 转变更还原。高级显微结构分析清楚地表明 SCC 沿晶界开始，表现出扩散诱导晶界迁移 (DIGM)，以及 Al 和 Ti 的富集。镍基合金中 SCC 的引发不是单一主导机制的结果，而是涉及 DIGM 与富铝和钛氧化物的形成之间的协同相互作用，促进 PIO 可以在施加的应力下断裂。