Abstract This study investigated the PbSCC of Alloy 690TT exposed to a caustic solution at 320 °C. Characterization of the resulting films indicates that lead is involved in the formation of oxides and evenly distributed in the films. TEM analysis was carried out to elucidate the role of lead in IGSCC by investigating the oxides at the crack tip. Lead penetrates into the crack tip and disperses in the intergranular oxides, enhancing the oxidation of grain boundaries. Thus, microcracks initiate within oxides under stress and connect with the main SCC crack stemming from the pit, resulting in propagation of the IGSCC.

中文翻译：

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690TT合金在含铅苛性碱溶液中应力腐蚀开裂机理

摘要 本研究调查了 690TT 合金暴露于 320 °C 苛性碱溶液中的 PbSCC。所得薄膜的表征表明铅参与氧化物的形成并均匀分布在薄膜中。通过研究裂纹尖端的氧化物，进行 TEM 分析以阐明铅在 IGSCC 中的作用。铅渗入裂纹尖端并分散在晶间氧化物中，增强了晶界的氧化。因此，微裂纹在应力作用下在氧化物内开始并与源自凹坑的主要 SCC 裂纹连接，导致 IGSCC 的扩展。