Irradiation assisted stress corrosion cracking (IASCC) is a form of intergranular stress corrosion cracking that occurs in irradiated austenitic alloys. It requires an irradiated microstructure along with high temperature water and stress. The process is ubiquitous in that it occurs in a wide range of austenitic alloys and water chemistries, but only when the alloy is irradiated. Despite evidence of this degradation mode that dates back to the 1960s, the mechanism by which it occurs has remained elusive. Here, using high resolution electron backscattering detection to analyze local stress-strain states, high resolution transmission electron microscopy to identify grain boundary phases at crack tips, and decoupling the roles of stress and grain boundary oxidation, we are able to unfold the complexities of the phenomenon to reveal the mechanism by which IASCC occurs. The significance of the findings impacts the mechanical integrity of core components of both current and advanced nuclear reactor designs worldwide.

中文翻译：

---

辐照如何促进晶间应力腐蚀裂纹的萌生

辐照辅助应力腐蚀开裂 (IASCC) 是一种发生在辐照奥氏体合金中的晶间应力腐蚀开裂。它需要经过辐照的微观结构以及高温水和应力。该过程无处不在，因为它发生在各种奥氏体合金和水化学物质中，但仅当合金受到辐射时才发生。尽管有证据表明这种降解模式可以追溯到 20 世纪 60 年代，但其发生的机制仍然难以捉摸。在这里，使用高分辨率电子背散射检测来分析局部应力应变状态，使用高分辨率透射电子显微镜来识别裂纹尖端的晶界相，并将应力和晶界氧化的作用解耦，我们能够揭示出裂纹尖端的复杂性。现象来揭示IASCC发生的机制。这些发现的重要性影响着全球当前和先进核反应堆设计的核心部件的机械完整性。