α-铁中位移级联过程中缺陷的生成和He-空位复合物的形成  

Defect production and formation of helium-vacancy clusters in cascades of α-iron with different concentration of helium

作　　者：杨莉[1] 祖小涛[1] 肖海燕[1] 杨树政[2] 刘柯钊[3] Fei Gao 

机构地区：[1]电子科技大学应用物理系 [2]西华师范大学物理与电子信息学院 [3]中国工程物理研究院四川材料与工艺研究所 [4]Pacific Northwest National Laboratory,Richland,WA 99352

出　　处：《物理学报》2005年第10期4857-4862,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10376006);新世纪优秀人才支持计划资助.~~

摘　　要：运用分子动力学方法研究了不同He浓度和不同级联能下含He的α-Fe低温时的位移级联过程.模拟的主要撞击原子(PKA)的能量(EP)(即级联能)从500eV变化到5keV,辐照温度为100K,He的浓度从1%变化到5%.比较了不同He浓度下的Fe-He混合物和纯α-Fe的位移级联过程,发现在含有He的α-Fe中总的Fe和He的Frenkel对与纯的α-Fe的Frenkel对的数目相当.当He的浓度较低时,含有He的α-Fe中的Frenkel对比α-Fe的要低,随He的浓度增加,有He的α-Fe中的Frenkel对比α-Fe中的高,这主要与He在金属中的性质有关.本研究证明了位移级联过程可以直接导致He泡的成核.对不同级联能和不同He浓度下Fe的位移级联过程的模拟,发现在同样的级联能下,随着He浓度的增加,He成团的几率增大;在同样的He浓度下,随着级联能的增加,He成团的几率也同样增加,并分析了级联下He泡的形成机制.The low-temperature displacement cascades in α-Fe with different concentrations of substitutional He atoms are simulated by molecular dynamics （MD） methods. Primary knock-on atom （PKA） energy, Ep, from 500eV to 5keV is considered for irradiation temperature of 10OK. The concentration of He in Fe varies from 1% to 5 % . The results are compared with those obtained in pure α-Fe. We find the number of Frenkel pairs （NF） in Fe with low concentration of He atoms is nearly equal to those in pure Fe, but increases with increasing He concentration. The present study demonstrates for the first time that Hevacancy bubbles can be nucleated directly from displacement cascades, even at low temperature at which the vacancies are not mobile. However, the efficiency of He-vacancy clusters increases with increasing the concentration of He for the same energy recoils, and increases with increasing Ep for the same concentration of He. The mechanisms of He bubble nucleation in displacement cascades are discussed in detail.

关 键 词：FE 位移级联 He-空位复合物 分子动力学 级联过程 位移 复合物 α-铁 Α-FE 浓度增加 

分 类 号：TL32[核科学技术—核技术及应用]