应力诱导中子辐照奥氏体钢空洞的相场模拟  

Stress-Induced Neutron Irradiation Voids of Austenite Steel Using Phase Field Method

作　　者：张伟[1] 程大钊 刘彩艳 马聪 吴璐[1] 张静[2] Zhang Wei;Cheng Dazhao;Liu Caiyan;Ma Cong;Wu Lu;Zhang Jing(The First Sub-Institute,Nuclear Power Institute of China,Chengdu 610005,China;State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China;School of Material Science and Engineering,Xi’an University of Technology,Xi’an 710048,China)

机构地区：[1]中国核动力研究设计院第一研究所,四川成都610005 [2]西北工业大学凝固技术国家重点实验室,陕西西安710072 [3]西安理工大学材料学院,陕西西安710048

出　　处：《稀有金属材料与工程》2024年第10期2926-2933,共8页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(U2267253,51704243);陕西省自然科学基础研究计划(2022JM-238)。

摘　　要：辐照空洞导致的辐照肿胀是堆芯长时服役奥氏体钢失效的重要原因。本工作采用介观尺度的相场模型耦合辐照速率理论和微弹性理论,研究外加全局应力和局域位错应力场对奥氏体Fe-Cr合金辐照空洞组织的影响。外加应力作用下空洞形核的孕育期缩短,空洞长大加速,沿着外加应力方向空洞形貌被拉长为纺锤形;相比无外加应力下,外加应力作用使空洞平均半径更大,空洞数量减少。外加应力越大,空洞平均半径越大、数量越少、体积分数越大,形貌改变越显著。位错偶极子和位错阵列的弹性应力场吸引空位在其位错核周围择优形核长大,且与无位错作用相比,位错应力作用下空洞数量增多、平均半径减小,最终体积分数基本不受位错影响。对比外加应力和位错应力场作用,全局应力引起的肿胀较位错更为显著。本研究结果可启发堆芯奥氏体钢组织老化和性能衰退评估。Irradiation swelling caused by irradiation voids is responsible for the failure of long-term serving austenite steel in the reactor core.A mesoscale phase field model coupled with rate theory and micro-elastic theory was used to investigate the stress effects on void microstructure of Fe-Cr austenite steel,when the applied global stress and local dislocation stress field were considered.Results show that the applied stress shortens the incubation period of nucleation of voids and accelerates the growth of voids,and the voids evolve into fusiform eventually.Voids in the stressed state have a larger radius and lower density compared with that in the stress-free state.The larger the applied stress,the larger the average radius and volume fraction,the smaller the number,and the more significant the morphology reconstruction.The local elastic stress field of dislocation dipole and dislocation array attracts vacancies to preferentially nucleate and grow around the dislocation nucleus.Compared with the dislocation-free system,the voids are denser and finer when dislocations exist,but the volume fraction of voids persists.In contrast,the applied stress should probably cause server swelling than dislocations in Fe-Cr alloys.The results of this study is conducive to the evaluation of microstructure aging and property decline of in-core austenitic steel.

关 键 词：速率理论 相场模拟 弹性应力 应力诱导空洞 空洞形貌 

分 类 号：TL341[核科学技术—核技术及应用]