第一性原理研究Al-Y合金在压力作用下的晶胞结构、力学性质、热力学性质和电子结构（英文）

Structure, Elastic Properties, Thermodynamic and Electronic Properties of Al-Y Alloy Under Pressure from First-principles Calculations

采用基于密度泛函理论的第一性原理研究了压力对Al-Y合金的晶胞结构、力学性质、热力学性质和电子结构的影响。结果表明:晶格常数、弹性常数和弹性模量的计算结果与先前理论计算和实验结果相一致;体模量、剪切模量、杨氏模量、泊松比和德拜温度随压力增大而增大,而热熔则随压力的增大而减小;德拜温度按顺序逐步降低;通过Pugh准则(GB)预测出AlY和Al_3Y相是塑性材料,并随压力的增大塑性增加,而Al_2Y相是脆性材料,其脆性并未随压力增大得到改善;最后还分析了压力对AlY、Al_2Y和Al_3Y相的态密度和电荷布局的影响。

The influence of pressure on structure,elastic properties,thermodynamics and electronic properties of Al-Y alloy were investigated using first-principles.The equilibrium lattice constant,elastic constants,and elastic modulus as calculated here agree with results of previous studies.Calculated results of bulk modulus B,shear modulus G,Young’s modulus E,Poisson’s ratio v and Debye temperatureΘD all increase as pressure increases,but the opposite is true for heat capacity cp.In addition,the Debye temperature for the phases declines gradually as follows：Al2YAl3YAlY.Additionally,the G/B ratio indicates that AlY and Al3Y are ductile materials,while Al2Y is a brittle material,and that the ductility of Al Y and Al3Y can be improved with increased pressure,while the brittleness of Al2Y does not improve with increased pressure.Finally,the paper presents and discusses calculations of density of states and charge populations as they are affected by pressure.