铁素体/马氏体钢在氧饱和LBE中的腐蚀和小样品拉伸行为  

Corrosion and Small Sample Tensile Behavior of Ferritic/Martensitic Steel in Oxygen Saturated Lead-bismuth Eutectic

作　　者：李世江 龚翱翔 孙璐 马雁[1] 秦博[2] 龙斌[2] 佟振峰 LI Shijiang;GONG Aoxiang;SUN Lu;MA Yan;QIN Bo;LONG Bin;TONG Zhenfeng(School of Nuclear Science and Engineering,North China Electric Power University,Beijing 102206,China;China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]华北电力大学核科学与工程学院,北京102206 [2]中国原子能科学研究院,北京102413

出　　处：《原子能科学技术》2025年第1期142-150,共9页Atomic Energy Science and Technology

基　　金：国家重点研发计划(2022YFB3707605)。

摘　　要：铁素体/马氏体(F/M)钢有望作为结构材料应用于铅冷快堆。但是,其与铅铋共晶(LBE)合金的相容性成为必须克服的难题。为研究F/M钢在高温氧饱和LBE中的相容性,采用慢应变速率拉伸试验和腐蚀试验在不同温度的LBE中对HT9钢的拉伸和腐蚀行为进行研究。通过多尺度复合表征技术对拉伸断口和腐蚀后的形貌及微观结构进行观测和标定。结果发现:350℃时HT9钢的断后伸长率为11.6%,表现出对LBE的高度脆化敏感;当温度继续升高到450~550℃时,材料的断裂模式由脆性断裂转变为塑性断裂。350℃时HT9钢表面氧化层由外磁铁矿和内铬铁矿尖晶石双重氧化层构成;550℃时表面氧化层由外磁铁矿、内铬铁矿及富Cr的IOZ三重氧化层构成。在应力集中和塑性变形的影响下,疏松的外磁铁矿不具备有效的保护作用,甚至从基体剥落。Ferritic/martensitic(F/M)steels are potentially applied as structural materials in the lead cooled fast reactor,a promising fourth-generation reactor that adopts lead-bismuth eutectic(LBE)as coolant.However,the F/M steels normally suffer from a LBE sensitivity,showing a liquid metal embrittlement(LME)and liquid metal corrosion(LMC)when exposed to the LBE.Here in this paper,in order to study the compatibility of F/M steel in oxygen saturated LBE at different temperatures,the stress corrosion behavior of HT9 steel was conducted by slow strain rate tensile(SSRT)tests and corrosion tests in LBE at different temperatures.Comprehensive microstructural characterizations from atomic-scale examinations to micro-scale fracture analyses including HAADF-STEM,SAED,HRTEMFFT,EBSD and SEM were performed to obtain the morphology and calibrate the crystallographic structure of tensile fracture and corrosion sample.The experimental results show that the total elongation of HT9 steel is 11.6%at 350°C in oxygen saturated LBE,which is sensitive to the embrittlement of liquid LBE.However,when the temperature increases to 450-550°C,the failure mode of the HT9 steel is dominated by the corrosion of LBE.The fracture mode changes from brittle fracture at 350℃to plastic fracture above 350℃and the total elongation is more than 2 times higher than that at 350℃.Through further characterization,it is found that the oxide layer is duplex,mainly composed of outer loose magnetite layer and inner chromite spinel layer when exposed HT9 steel in oxygen saturated liquid LBE at 350℃,while the magnetite layer cannot prevent the LBE to wet the HT9 steel matrix.Nevertheless,when exposed the sample in 550℃LBE,a triplex oxide layer structure includes a thin Cr-rich and Fe-poor oxide layer(IOZ),the magnetite and chromite spinel layer are found near the interface of the HT9 steel matrix.The commonality is that the magnetite layer at different temperatures both has no effective protection to HT9 steel matrix,and even peels off from the matrix.Throu

关 键 词：铁素体/马氏体钢 HT9钢 铅铋共晶合金 液态金属脆化 液态金属腐蚀 温度 氧化层 

分 类 号：TL341[核科学技术—核技术及应用]