Abstract： With the substitution of part Mg in LaMg3 by Cu, the elastic constants CH and C12 increase while C44 decreases, implying an enhanced Poisson effect and smaller resistance to 〈001〉（100） shear. Furthermor...Abstract： With the substitution of part Mg in LaMg3 by Cu, the elastic constants CH and C12 increase while C44 decreases, implying an enhanced Poisson effect and smaller resistance to 〈001〉（100） shear. Furthermore, the bulk modulus B increases, while the shear modulus G, elastic modulus E and anisotropie ratio A are reduced. The calculated Debye temperature of LaCuMg2 is lower, implying the weaker interaction between atoms in LaCuMg2. Then, the stress-strain curves in entire range and the ideal strength at critical strain are studied. The present results show that the lowest ideal tensile strength for LaMg3 and LaCuMg2 is in the 〈100〉 direction. The ideal shear strength on the 〈 1 ^-1 0〉（110） slip system of LaMg3 is greater than LaCuMg2. The density of states and charge density distribution are further studied to understand the inherent mechanism of the mechanical properties.展开更多
基金Project(51071053)supported by the National Natural Science Foundation of ChinaProject(X071117)supported by the Scientific Research Foundation of Guangxi University,ChinaProject(KF0803)supported by the Open Project of Key Laboratory of Materials Design and Preparation Technology of Hunan Province,China
文摘Abstract： With the substitution of part Mg in LaMg3 by Cu, the elastic constants CH and C12 increase while C44 decreases, implying an enhanced Poisson effect and smaller resistance to 〈001〉（100） shear. Furthermore, the bulk modulus B increases, while the shear modulus G, elastic modulus E and anisotropie ratio A are reduced. The calculated Debye temperature of LaCuMg2 is lower, implying the weaker interaction between atoms in LaCuMg2. Then, the stress-strain curves in entire range and the ideal strength at critical strain are studied. The present results show that the lowest ideal tensile strength for LaMg3 and LaCuMg2 is in the 〈100〉 direction. The ideal shear strength on the 〈 1 ^-1 0〉（110） slip system of LaMg3 is greater than LaCuMg2. The density of states and charge density distribution are further studied to understand the inherent mechanism of the mechanical properties.
