材料的液态金属脆化(LME)是限制铅冷快堆发展的主要问题，本文开展了P92钢在液态Pb-Bi共晶(LBE)环境中的慢应变速率拉伸行为研究，重点考察了温度(150–500 ℃)、溶解氧浓度(10^-10%至饱和氧，质量分数)以及应变速率(4 × 10^-7~4 × 10^-4 s^-1)对其脆化敏感性的影响，系统考察了氧化膜完整性和液态LBE中的Pb/Bi原子扩散吸附对P92钢LME行为的影响，深入分析了溶解氧和应变速率在材料断裂中的作用机理。结果表明，P92钢在饱和氧条件下未表现出明显脆性，仅在高应变速率条件下断口边缘观察到少量准解理开裂特征；而溶解氧浓度较低时，断口为典型的准解理开裂特征，且在低应变速率条件下脆性更强。

Liquid metal embrittlement (LME) refers to the phenomenon wherein the ductility of a solid metal markedly decreases upon contact with a liquid metal. This issue is a critical constraint in the development of lead-cooled fast reactors (LFRs). The commonly accepted mechanism involves the adsorption of liquid Pb–Bi atoms at the crack tips of solid metals, which alters the bonding interactions, lowers the critical stress for rupture, and ultimately causes embrittlement. 9Cr ferritic/martensitic steels are considered potential candidate materials for LFRs. In this study, the slow strain rate tensile behavior of P92 steel was investigated in liquid lead–bismuth eutectic (LBE), focusing on the effects of temperature (150–500 °C), strain rate (4 × 10⁻⁷–4 × 10⁻⁴ s⁻¹), and dissolved oxygen concentration (from 10⁻¹⁰ mass fraction to oxygen saturation). The results showed that no significant embrittlement occurred in oxygen-saturated conditions. In contrast, high embrittlement sensitivity was observed in oxygen-deficient LBE at low strain rates. At high oxygen concentrations, a protective oxide film forms on the surface, effectively isolating the solid metal from liquid LBE, thereby preventing embrittlement. However, this protective effect diminishes significantly if the integrity of the oxide film is compromised. High strain rates promote mechanical damage to the oxide layer, which facilitates LME. In oxygen-poor LBE, the protective oxide film barely forms, leading to direct exposure of the steel matrix to the liquid LBE. This exposure causes dissolution corrosion, where pits formed by metal dissolution act as crack initiation sites owing to localized stress concentration, promoting LME. Interestingly, excessively high strain rates can accelerate crack propagation to such an extent that the crack tip advances before sufficient adsorption of Pb/Bi atoms occurs. This rapid progression inhibits the embrittling action of the liquid metal, thereby reducing the LME effect under low dissolved oxygen conditions.