摘要
利用基于密度泛函理论的Castep软件构建了Mg_(15)X(X=Mg,Al,Zn,Ca,Nd,Er)固溶体模型。采用第一性原理计算了其晶格常数、结构稳定性及电子特性。结果表明:相对于Mg_(16)结构而言,Mg_(15)X(X=Al,Zn,Ca,Nd,Er)固溶体结构的c/a值均有所减小,其中Mg_(15)Nd和Mg_(15)Er固溶体的c/a值减小幅度较大,预测在镁基体中添加适量稀土元素Nd或Er,有利于提高镁合金的延展性。Mg_(15)X(X=Mg,Al,Zn,Ca,Nd,Er)结构的形成热和结合能的计算结果均为负值,这表明这些固溶体结构能稳定存在,镁合金中Al、Nd、Er的固溶强化作用优于Ca、Zn的。Mg_(15)Er与Mg_(15)Nd结构稳定性较好的电子机制为Mg(s)、(p)分别与Er(d)、(f)和Nd(d)、(f)轨道价电子强烈杂化,表现出较强的共价键。
The solid solution model of Mg_(15)X(X=Mg,Al,Zn,Ca,Nd,Er)was constructed by Castep software based on density functional theory,and the lattice constant,structural stability and electronic characteristics of the soulid solution were calculated by first principles.The results show that in contrast to the Mg_(16) structure,the c/a values of Mg_(15)X(X=Al,Zn,Ca,Nd,Er)solid solution structures decrease,and the reducing amplitude of c/a for Mg_(15)Nd and Mg_(15)Er is more than other solid solution structures.So,it can be predicted that the ductility of magnesium alloy improves by adding appropriate amount of rare earth element,Nd or Er.The calculated values of forming heat and cohesive energy of Mg_(15)X(X=Mg,Al,Zn,Ca,Nd,Er)solid solution structures are negative,indicating that the solid solution structures can exist stably.Furthermore,the solid solution strengthening of Al,Nd and Er in magnesium alloy is stronger than that of Ca and Zn.In addition,the electron mechanism of Mg_(15)Er and Mg_(15)Nd structures with excellent stability is that Mg(s)and(p)are strongly hybridized with valence electrons in Er(d),(f),Nd(d)and(f)orbitals respectively,showing strong covalent bond.
作者
孙丽
崔晓明
白朴存
杜赵新
王争光
刘永宏
SUN Li;CUI Xiaoming;BAI Pucun;DU Zhaoxin;WANG Zhengguang;LIU Yonghong(School of Materials Science and Engineering,Inner Mongolia University of Technology,Hohhot 010051,China)
出处
《热加工工艺》
北大核心
2022年第8期43-47,共5页
Hot Working Technology
基金
内蒙古科技计划资助项目(201802029)
内蒙古自治区科技重大专项资助项目(zdzx2018031)
内蒙古自治区自然科学基金资助项目(2020MS05064,2018MS05056)。
