摘要
Fe-Cr合金作为包壳材料在高温高辐照强度等极端环境下服役,产生空位和间隙原子等辐照缺陷,辐照缺陷簇聚诱发空洞、位错环等缺陷团簇,引起辐照肿胀、晶格畸变,导致辐照硬化或软化致使材料失效.理解辐照缺陷簇聚和长大过程的组织演化,能更有效调控组织获得稳定服役性能.本文采用相场法研究Fe-Cr合金中空洞的演化,模型考虑了温度效应对点缺陷的影响以及空位和间隙的产生和复合.选择400—800 K温度区间、0—16 dpa辐照剂量范围的Fe-Cr体系为对象,研究在不同服役温度和辐照剂量下的空位扩散、复合和簇聚形成空洞的过程.在400—800 K温度区间,随着温度的升高,Fe-Cr合金空洞团簇形核率呈现出先升高后下降的趋势.考虑空位与间隙的重新组合受温度的影响可以很好地解释空洞率随温度变化时出现先升高后降低的现象.由于温度的变化将影响Fe-Cr合金中原子离位阀能,从而影响产生空位和间隙原子.同一温度下,空洞半径和空洞的体积分数随辐照剂量的增大而增大.辐照剂量的增大,级联碰撞反应加强,空位与间隙原子大量产生,高温下空位迅速的扩散聚集在Fe-Cr合金中将形成更多数量以及更大尺寸的空洞.
As cladding materials,Fe-Cr alloys are used in the extreme environments of high temperature,high pressure,and energetic particle radiation,thus generating irradiation defects such as vacancies and interstitials.The clustering of irradiation defects leads the voids or dislocation loops to form,resulting in irradiation swelling and lattice distortion,and further radiation hardening or softening,finally,material failure.It is beneficial to tailor desired microstructures and obtain stable service performances by understanding defects cluster and voids formation process.In this paper,the phase-field method is employed to study the evolution of voids of Fe-Cr alloy.In the model the temperature effects on point defects and generation/recombination of vacancies and interstitials are taken into consideration.The 400–800 K temperature range and 0–16 dpa radiation dose range are selected,in which the voids’formation process including generation and recombination,as well as vacancy clustering caused by vacancy diffusion,is studied for Fe-Cr alloy.The nucleation rate of the void cluster shows a trend of first increasing and then decreasing with temperature increasing from 400 to 800 K.This phenomenon is related to complex interactions among defects concentration,atomic diffusion,recombination,nucleation,and growth conditions.At a given temperature,the average radius and the volume fraction of the voids grow bigger as the radiation dose increases.With the increase of irradiation dose,the cascade collision reaction is strengthened,and the number of Frenkel defect pairs is also increases.A large number of vacancies and interstitial atoms are generated,and the rapid diffusion and accumulation of vacancies in the Fe-Cr alloy at high temperature form a larger number and larger size of voids.The incubation period of vacancy clusters and voids are quite different due to the influence of irradiation temperature and dose.The higher the irradiation dose,the shorter the incubation period is.The relationship between the incubation p
作者
杨辉
冯泽华
王贺然
张云鹏
陈铮
信天缘
宋小蓉
吴璐
张静
Yang Hui;Feng Ze-Hua;Wang He-Ran;Zhang Yun-Peng;Chen Zheng;Xin Tian-Yuan;Song Xiao-Rong;Wu Lu;Zhang Jing(School of Material Science and Engineering,Xi’an University of Technology,Xi’an 710048,China;School of Material Science and Engineering,Northwestern Polytechnical University,Xi’an 710072,China;The First Sub-institute,Nuclear Power Institute of China,Chengdu 610005,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2021年第5期208-216,共9页
Acta Physica Sinica
基金
国家自然科学基金(批准号:51704243,51674205,51601185)
国防基础科研计划(批准号:JCKY2017201C016)
中国博士后科学基金(批准号:2015M582575)
国家重点研发计划(批准号:2016YFB07001)资助的课题.
关键词
相场法
空洞演化
辐照剂量
级联碰撞
phase-field method
void evolution
irradiation dose
cascade collision
