时效对NiCrMoV异种接头焊缝性能和组织的研究
郑琦亚
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作者单位：上海交通大学上海市激光制造中心与材料改性重点实验室
中文关键字：NiCrMoV钢；焊接接头；微观组织；时效脆性；
英文关键字：NiCrMoV steel; welding joint; microstructure; aging brittleness
中文摘要：本文对在350℃长时间时效的异种NiCrMoV钢接头进行冲击试验发现，时效处理后焊缝冲击韧性下降明显；通过光学显微镜（OM）、扫描电镜（SEM）、电子背散射衍射分析（EBSD）、化学成分和微观组织分析，结果表明：M3C碳化物沿晶界析出、溶质原子N在晶界偏聚和时效过程中残余奥氏体的热失稳分解是导致异种NiCrMoV钢接头时效后性能下降的主要原因。
英文摘要：According to impact test on the weld metal in dissimilar steel welding joint of different NiCrMoV steels after long-time aging at temperature 350, it shows that long-time aging cause performance degradation. The reasons of performance degradation after long-time aging were studied by OM, SEM, EBSD and chemical analysis. The results revealed that carbides segregation along grain boundaries，the segregation of solute atoms N in grain boundaries and retained austenite thermal instability deposition are main reasons for aging brittleness.