钨中溶质原子铬与空位的相互作用的第一性原理计算研究  

Interaction Between the Solute Cr Atoms and Vacancy in W-Cr Alloys Using First-Principles Calculation

作　　者：何梓荐 黄雪飞[2] 乐国敏[3] 付宝勤 He Zijian;Huang Xuefei;Le Guomin;Fu Baoqin(Key Lab for Radiation Physics and Technology,Ministry of Education,Institute of Nuclear Science and Technology,Sichuan University,Chengdu 610064,China;College of Materials Science and Engineering,Sichuan University,Chengdu 610065,China;China Academy of Engineering Physics,Mianyang 621908,China)

机构地区：[1]四川大学原子核科学技术研究所辐射物理及技术教育部重点实验室,四川成都610064 [2]四川大学材料科学与工程学院,四川成都610065 [3]中国工程物理研究院,四川绵阳621908

出　　处：《稀有金属材料与工程》2020年第8期2691-2696,共6页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51501119)。

摘　　要：基于第一性原理方法,对W-Cr合金的溶质原子Cr占位、Cr与空位的相互作用及Cr含量对其影响规律进行了计算研究。发现相比于间隙位置,原子Cr更易占据置换位置,W中溶质Cr有偏聚的趋势;在辐照环境下,空位和自间隙原子均易与溶质原子Cr相结合,易加速W中富Cr相的析出;随Cr含量的增加,体系的形成能线性增加,因而结构越不稳定。研究还发现超胞中单原子Cr的第2近邻空位的形成能最低,且低于W的本征空位形成能,因而溶质Cr与空位之间存在微弱的吸引;对于同一Cr含量,不同构型的空位形成能及空位和Cr的结合能均不同,且Cr含量越高,数值越分散;随着Cr含量的增加,平均空位形成能及空位与Cr的平均结合能均略有下降,因而溶质原子Cr附近空位更易形成,空位浓度更高,同样也表明溶质Cr与空位有微弱的吸引。这些结论将有助于深入理解W中溶质元素存在条件下辐照缺陷演化过程的微观物理机制。The occupation of solute Cr atoms,the interaction between solute Cr atoms and vacancy,and the effect of the solute Cr concentration were studied by first-principles calculation.The results show that the solute Cr atoms prefers to occupy the substitutional position with formation energy of^0.3 eV.The point defects induced by radiation will facilitate the segregation of the solute Cr atoms.The formation energy of solute Cr increases linearly with the increasing of the concentration of solute Cr,indicating a strong segregation.It is also found that the formation energy of the second nearest neighbor vacancy of single atom Cr in super-cell is the lowest,even lower than the intrinsic vacancy formation energy of W,so there is a weak attraction between solute Cr and the vacancy.For the same Cr content,the vacancy formation energy of different configurations and the binding energy of vacancy and Cr are different,and the higher the Cr content is,the more dispersed the values are.With the increase of Cr content,the average vacancy formation energy and the average binding energy of the vacancy and Cr decrease slightly,so the vacancy near the solute atom Cr is more easily formed and the vacancy concentration is higher,which also indicates that there is weak attraction between the solute Cr and the vacancy.These results are important for understanding the long-term micro-structural evolution of materials under irradiation.

关 键 词：第一性原理 钨-铬合金 空位缺陷 

分 类 号：O469[理学—凝聚态物理] TF841.1[理学—电子物理学]