【作者】 赵宇翔； 熊茹； 乔英杰； 刘桂良； 唐睿；

【Author】 ZHAO Yu-xiang;XIONG Ru;QIAO Ying-jie;LIU Gui-liang;TANG Rui;National Key Laboratory of Reactor Fuel and Material,Nuclear Power Institute of China;School of Materials Science and Chemical Engineering,Harbin Engineering University;

【机构】 中国核动力研究设计院反应堆燃料及材料重点实验室； 哈尔滨工程大学材料科学与化学工程学院；

【摘要】 在超临界水冷堆(SCWR)的设计中,运行温度、压力、燃耗和辐照损伤都非常高。正确选择堆内结构材料,掌握其关键应用性能对SCWR的研发具有重要意义。本文采用旋转弯曲的加载方式完成了商用奥氏体合金6XN、825在室温、550℃空气中的疲劳试验,对试验数据进行了分析和处理,绘制了S-N曲线,对疲劳断口进行了扫描电镜(SEM)分析。结果表明,两种Fe-Cr-Ni合金的室温疲劳极限大小顺序为825<6XN,与静强度顺序一致;高温会加速试样的氧化,降低材料的疲劳寿命,并且6XN下降趋势稍大,对温度更敏感,使两种合金550℃疲劳极限变得很接近;而825合金对应力循环次数更敏感;疲劳极限与经验公式计算值的比较表明,两种合金具有较好的抗高周疲劳性能;疲劳过程为裂纹源产生、扩展和断裂,最后断裂区具有韧窝特征。研究结果为SCWR概念设计提供了参考和输入。更多还原

【Abstract】 In the design for supercritical water reactor(SCWR),the operating temperature,pressure,burn up and irradiation damage are very high,so it seems vital to make correct choice of structural materials in core and obtain their key application behavior which would beneficial the research and development of SCWR.In this paper,the high cycle fatigue(HCF) tests of commerce austenite alloys including 6XN and 825 were conducted under bending and rotating loads at room temperature(RT) as well as at 550℃ in air.The experimental data were analyzed and the S-N curves were processed,the fracture morphology was also observed by SEM.The results indicate that the fatigue limited stresses at RT for the 2 Fe-Cr-Ni alloy-were in such order of 825<6XN,which consistent with the order of their tensile strength.Elevated temperature would accelerate the oxidation of the specimen and therefore the fatigue life would decrease,among them 6XN was more sensitive to high temperature with the larger decreasing tendency which make the fatigue limited stress of the two alloys more closer at 550℃.While 825 is more sensitive to the stress cycles.All the two alloys have good resistance to high cycle fatigue when comparing their experimental data with the calculated value from the empirical formula.The fracture morphology presents areas of crack initiation,crack growth and fracture,the fracture area has much dimples.This work can be applied to the conceptional design for SCWR.更多还原