超级奥氏体不锈钢AL-6XN在超临界水环境中的应力腐蚀性能
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摘要
研究了超级奥氏体不锈钢AL-6XN在550℃/25MPa和650℃/25MPa超临界水环境中的应力腐蚀开裂敏感性,同时还研究了辐照对其在550℃/25MPa的超临界水环境中应力腐蚀开裂敏感性的影响。通过慢应变拉伸试验得到相应的应力-应变曲线,通过扫描电镜(SEM)得到试样断口和侧面的形貌。结果表明,在550℃/25MPa的工况下,AL-6XN辐照前后的屈服强度、抗拉强度和延伸率并没有发生明显变化,应力腐蚀开裂倾向均较小。当温度升高到650℃时,AL-6XN的应力腐蚀敏感性明显增加,具有较大的应力腐蚀开裂倾向。本研究还发现未辐照过的AL-6XN在550℃/25MPa的工况下发生了动态应变时效现象。
Stress corrosion cracking(SCC)susceptibilities of superaustenitic stainless steel AL-6XN in supercritical water(SCW)at 550℃/25MPa and 650℃/25MPa were evaluated,and the effects of irradiation on its susceptibility to SCC in SCW at 550℃/25MPa was also evaluated.Slow strain rate tests(SSRT)were used to obtain the stressstrain curves and scanning electron microscopy(SEM)was used to observe the fracture surfaces.The results show that the mechanical strength and elongation of AL-6XN have no obvious change after being irradiated,and the susceptibility to SCC was low.The susceptibility to SCC increased obviously when the temperature was up to 650℃, which means the susceptibility of AL-6XN is high.It was also observed that AL-6XN showed dynamic strain aging(DSA)phenomenon in SCW at 550℃/25MPa.
Stress corrosion cracking(SCC)susceptibilities of superaustenitic stainless steel AL-6XN in supercritical water(SCW)at 550℃/25MPa and 650℃/25MPa were evaluated,and the effects of irradiation on its susceptibility to SCC in SCW at 550℃/25MPa was also evaluated.Slow strain rate tests(SSRT)were used to obtain the stressstrain curves and scanning electron microscopy(SEM)was used to observe the fracture surfaces.The results show that the mechanical strength and elongation of AL-6XN have no obvious change after being irradiated,and the susceptibility to SCC was low.The susceptibility to SCC increased obviously when the temperature was up to 650℃, which means the susceptibility of AL-6XN is high.It was also observed that AL-6XN showed dynamic strain aging(DSA)phenomenon in SCW at 550℃/25MPa.
引文
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[2]SRIDHARANK,ZILLMERA,LICHT J R,et al.Corrosion behavior of candidate alloys for supercritical water reactors[C]//Proc ICAPP′04 Pittsburgh P A,USA:[s.n.],2004:4136.
[3]李光辉,彭君,袁义帆,等.硫酸根离子和电极电位对异材焊接件A508/52M在高温水中应力腐蚀破裂的影响[J].理化检验-物理分册,2013,49(6):357-361.
[4]孟丽君,庞淦文,邢辉,等.AL-6XN超级奥氏体钢高温拉伸时的动态应变时效[J].材料热处理学报,2010,31(4):50-54.
[5]KATADA Y,NAGATA N.The effect of temperature on fatigue crack growth behavior of a low-alloy pressure vessel steel in a simulated BWR environment[J].Corrosion Science,1985,25(8/9):693-704.
[6]ATKINSON J D,YU J.Role of dynamic strain ageing in the environment assisted cracking observed in pressure vessel steels[J].Fatigue Fract Eng Mater Struct,1997,20(1):1-12.
[7]钱匡武,彭开萍,陈文哲,等.金属动态应变时效现象中的“锯齿屈服”[J].福建工程学院学报,2003,1(1):4-8.