摘要
空位团簇是铝合金中最常见的缺陷之一。利用基于密度泛函理论的第一性原理计算,研究铝中孔洞、层错四面体(SFT)和{111}平面上的空位板等小空位团簇的能量学,发现文献报道的单空位形成能的显著差异主要与它们所使用的交换相关泛函数有关,LDA是Al中单空位形成能最可靠的近似,其次是PBE、PBEsol、PW91和AM05。本文结果证实Al中的双空位在能量上是不稳定的。此外,任何结构中小于5的空位团簇相对于相应数量的孤立单空位都是不稳定的。SFT是大多数小空位团簇中最稳定的结构,其次是孔洞和空位板。这些结果有助于理解实验观测到的铝中空位团簇的尺寸分布。
The vacancy cluster is one of the most common defects in aluminum alloys.Using density-functional theory-based first-principles calculations,the energetics of small vacancy clusters in aluminum,including voids,stacking fault tetrahedra(SFT),and vacancy platelets on the{111}plane,was investigated.It is found that the significant difference in monovacancy formation energies reported in literatures is mainly related to their used exchange-correlation functions.On average,LDA is the most reliable approximation for the monovacancy formation energies in Al,followed by PBE,PBEsol,PW91,and AM05.The results in this work confirm that the divacancy in Al is indeed energetically unfavorable.Moreover,vacancy clusters with a size smaller than five in any form are unstable against their corresponding number of isolated monovacancies.The SFT is the most stable form of most small vacancy clusters,followed by the void and vacancy platelet.These results are helpful to understand the experimentally observed size distributions of vacancy clusters in Al.
作者
苏恬莉
孔祥山
陈良
赵国群
张存生
Tian-li SU;Xiang-shan KONG;Liang CHEN;Guo-qun ZHAO;Cun-sheng ZHANG(Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials,Ministry of Education,Shandong University,Jinan 250061,China)
基金
Key Research and Development Program of Shandong Province,China (No. 2021ZLGX01)
the National Natural Science Foundation of China (No. 52071190)
the Shandong Provincial Natural Science Foundation,China (No. ZR2021YQ34)。
关键词
第一性原理
铝
单空位
双空位
空位团簇
层错四面体
空位板
first-principles
Al
monovacancy
divacancy
vacancy clusters
stocking fault tetrahedra
vacancy platelet
