Structural, thermodynamics and elastic properties of Mg_(17)Al_(12), Al_2Y and Al_4Ba phases by first-principles calculations  

作　　者：黄志伟 赵宇辉 侯华 赵宇宏 牛晓峰 韩培德 

机构地区：[1]College of Materials Science and Engineering,North University of China [2]Department of Mechanical and Electronic Engineering,Hebei College of Industry and Technology [3]College of Materials Science and Engineering,Taiyuan University of Technology

出　　处：《Journal of Central South University》2012年第6期1475-1481,共7页中南大学学报（英文版）

基　　金：Project(2011DFA50520) supported by the International Cooperation of Ministry of Science and Technology of China;Project(50975263) supported by the National Natural Science Foundation of China;Project(2010-78) supported by the Shanxi Provincial Foundation for Returned Scholars,China

摘　　要：Structural stabilities, thermodynamics stabilities, elastic properties and electronic structures of Mgl7Al12, Al2Y and AlaBa phases were analyzed by first-principles calculations with Castep and Drool3 program based on the density functional theory. The calculated results of heat of formation indicate that AI2Y phase has the strongest alloying ability. The calculated thermodynamic properties show that the thermal stability of these compounds gradually increases in the order ofMgl7Al12, A12Y and Al4Ba phases. Y or Ba addition to the Mg-Al alloys could improve the heat resistance. The calculated bulk modulus B, shear modulus G, elastic modulus E and Poisson ratio v show that the adding Y or Ba to Mg-Al alloys could promote the brittleness and stiffness, and reduce tenacity and plasticity by forming Al4Ba and Al2Y phases. The calculated cohesive energy and density of state （DOS） show that Al2Y has the strongest structural stability, then AlaBa and finally Mg17Al12. The calculated electronic structures show that Al2Y has the strongest structure stability because of the strong ionic bonds and covalent bonds combined action.Structural stabilities, thermodynamics stabilities, elastic properties and electronic structures of Mg17Al12, Al2Y and Al4Ba phases were analyzed by first-principles calculations with Castep and Dmol3 program based on the density functional theory. The calculated results of heat of formation indicate that Al2Y phase has the strongest alloying ability. The calculated thermodynamic properties show that the thermal stability of these compounds gradually increases in the order of Mg17Al12, Al2Y and Al4Ba phases. Y or Ba addition to the Mg-Al alloys could improve the heat resistance. The calculated bulk modulus B, shear modulus G, elastic modulus E and Poisson ratio ν show that the adding Y or Ba to Mg-Al alloys could promote the brittleness and stiffness, and reduce tenacity and plasticity by forming Al4Ba and Al2Y phases. The calculated cohesive energy and density of state (DOS) show that Al2Y has the strongest structural stability, then Al4Ba and finally Mg17Al12. The calculated electronic structures show that Al2Y has the strongest structure stability because of the strong ionic bonds and covalent bonds combined action.

关 键 词：Mg-Al alloys thermodynamics properties elastic properties electronic structure FIRST-PRINCIPLES 

分 类 号：TG146.22[一般工业技术—材料科学与工程]