The corrosion behavior of 310S austenitic stainless steel, subjected to different surface treatments machined (MA), sandblasting (SB), and polishing (PO), was exposed to a 550°C supercritical water (SCW) environment. The aged samples were analyzed using variable‐energy slow positron beam techniques. The obtained results revealed that the plastic deformation of the near‐surface region of the MA and SB samples was substantially recovered in the SCW conditions. At least two distinct oxide layers formed, and the oxidation process created a Fe/Cr depletion zone in the inner layer. Various surface treatments, however, led to different corrosion profiles. The depth profile of slow positron beam characterization suggests that significant residual stress and deformation zones on the surfaces of the sandblasted samples probably provided a diffusion path for the oxidation of the 310S. Only the SB samples exhibited a negative weight change after SCW exposure. At the same time, the SB samples showed the highest concentration of the positron traps in this region, which was explained by open‐volume defects associated with the microcracks introduced by sandblasting.

中文翻译：

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慢正电子法研究310S奥氏体不锈钢不同表面处理对超临界水中腐蚀行为的影响

经过机械加工（MA）、喷砂（SB）和抛光（PO）不同表面处理的310S奥氏体不锈钢暴露于550°C超临界水（SCW）环境中的腐蚀行为。使用可变能量慢正电子束技术对老化样品进行了分析。所得结果表明，MA 和 SB 样品近地表区域的塑性变形在 SCW 条件下基本恢复。形成了至少两个不同的氧化物层，并且氧化过程在内层中形成了 Fe/Cr 贫化区。然而，不同的表面处理会导致不同的腐蚀情况。慢速正电子束表征的深度剖面表明，喷砂样品表面上显着的残余应力和变形区域可能为 310S 的氧化提供了扩散路径。在 SCW 暴露后，只有 SB 样品表现出负重量变化。同时，SB 样品在该区域显示出最高浓度的正电子陷阱，这是由与喷砂引入的微裂纹相关的开放体积缺陷来解释的。