过渡金属铝化物FeAl和CoAl弹性性质的第一性原理研究  

First-principles study on the elastic properties of the transitionmetal aluminides:FeAl and CoAl

作　　者：耿晓菊[1] 武少华[2] 冯明海[1] 李冉[1] 

机构地区：[1]信阳师范学院物理电子工程学院,信阳464000 [2]重庆大学物理学院,重庆400045

出　　处：《原子与分子物理学报》2014年第5期774-780,共7页Journal of Atomic and Molecular Physics

基　　金：河南省教育厅科学技术研究重点项目(12A140010)

摘　　要：本文通过第一性原理计算(密度泛函理论结合均匀形变方法)得到过渡金属铝化物FeAl和CoAl的二阶和三阶弹性常数,这些弹性常数是通过拟合计算出的能量与应力关系得到的.计算结果和理论数据及实验值符合的很好.接下来本文又研究了FeAl和CoAl在不同压强下的弹性性质.不同压强下的弹性常数Cij,体模量B,剪切模量G,泊松比σ也成功的得到了.B/G比值和柯西压强PC都表明在零压下FeAl和CoAl表现出脆性.在压强小于60GPa的情况下,增大压强可以增强它们的韧性,但它们始终表现为脆性.The second-and third-order elastic constants of the B2-type translation-metal aluminides FeAl and CoAl have been calculated by using first-principles calculations based on density functional theory , in combination with the scheme of homogeneous deformation ,they are obtained by fitting the polynomi-als to the calculated energy-strain relationships .The calculated results are in good agreement with the a-vailable theoretical values and experimental data .We have also investigated the elastic properties of FeAl and CoAl under high pressures .The elastic constants Cij ,bulk modulus B ,shear modulus G and Pois-son’s ratio σ,as a function of pressure are presented .Through the Pugh ratio B/G and Cauchy pressure PC under different pressures ,the B2-type translation-metal aluminides FeAl and CoAl are predicted to have brittle behaviors at zero pressure .The pressure could yield improved ductility of FeAl and CoAl without significant changes at P ＆lt; 60GPa ,but they have brittle behaviors in the pressure range of 0-60GPa .

关 键 词：过渡金属 弹性常数 第一性原理 均匀形变 

分 类 号：O469[理学—凝聚态物理]