【摘要】 本研究聚焦于含硅铁素体/马氏体钢SIMP钢,着力探究铅铋共晶合金（LBE）的温度与应变速率如何对其液态金属脆化效应（LME）敏感性产生影响,揭示背后的作用机制。研究采用经过较低回火温度（500℃）处理的SIMP钢,以此模拟辐照硬化状态,进而获取硬化后材料在LBE环境中的LME敏感性。通过在不同温度的氩气和饱和氧LBE环境中,以不同应变速率对低温回火（500℃）的SIMP钢开展慢应变速率拉伸试验（SSRT）,并与正常回火（760℃）的SIMP钢进行对比分析。研究结果表明,500℃回火后的试样在350℃和400℃的LBE中呈现出显著的LME效应,具体表现为总断裂伸长率显著降低以及断口表面呈现准解理断裂特征;而当温度升高至550℃时,试样的总断裂伸长率完全恢复,断口呈现韧性断裂,表明此时LME现象消失。此外,正常回火（760℃）的SIMP钢在相同试验条件下未出现LME现象。同时,针对应变速率对500℃回火的SIMP钢LME敏感性的影响规律研究发现,在低应变速率(2×10^-6 s^-1)和高应变速率(1×10^-5 s^-1)时均会发生LME,但低应变速率下LME敏感性更高。研究结论为深入理解SIMP钢在LBE环境中的服役性能提供了重要依据。更多还原

【Abstract】 This work systematically examines the effects of temperature and strain rate on liquid metal embrittlement（LME） susceptibility of silicon-enhanced ferritic/martensitic SIMP steel in lead-bismuth eutectic（LBE） environments,with emphasis on elucidating the underlying mechanisms.To simulate irradiation-induced hardening,SIMP steel was tempered at 500 ℃,a reduced temperature compared to conventional processing.Slow strain rate tensile（SSRT） tests were conducted on 500 ℃-tempered specimens in both argon and oxygen-saturated LBE at temperatures ranging from 350 ℃ to 550 ℃,with strain rates varying between 2×10^-6 s^-1 and 1×10^-5 s^-1.Comparative analyses were performed against reference specimens tempered at 760 ℃.Results demonstrated threre is a pronounced LME susceptibility in 500 ℃-tempered specimens at 350 ℃ and 400 ℃,evidenced by a marked reduction in total elongation and quasi-brittle fracture morphology.Notably,this embrittlement vanishes at 550℃,where ductile fracture characteristics and full elongation recovery are observed.In contrast,760 ℃-tempered specimens exhibited no LME across all tested conditions.Strain rate dependence studies reveal that LME persists at both low(2×10^-6 s^-1) and high(1×10^-5 s^-1) strain rates for 500℃-tempered steel;however,sensitivity is significantly amplified at lower strain rates.The research results should provide an important basis for understanding the service performance of SIMP steel in LBE environment.更多还原