First-principles study on mechanical properties of LaMg3 and LaCuMg2
来源期刊：中南大学学报(英文版)2014年第6期
论文作者：WANG Ming-hui(王明辉) PAN Rong-kai(潘荣凯) LI Peng-bo(李鹏博) BIAN Nan(卞楠) TANG Bi-yu(唐壁玉) PENG Li-ming(彭立明) DING Wen-jiang(丁文江)
文章页码：2136 - 2142
Key words：first-principle calculations; elastic constant; ideal strength; mechanical properties; electronic structure
Abstract: With the substitution of part Mg in LaMg3 by Cu, the elastic constants C11 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 anisotropic 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 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.
WANG Ming-hui(王明辉)1, PAN Rong-kai(潘荣凯)1, LI Peng-bo(李鹏博)1, BIAN Nan(卞楠)1, TANG Bi-yu(唐壁玉)1, 2, PENG Li-ming(彭立明)3, DING Wen-jiang(丁文江)3
(1. School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China;
2. Department of Physics, Xiangtan University, Xiangtan 411105, China;
3. Light Alloy Net Forming National Engineering Research Center, School of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai 200030, China)
Abstract:With the substitution of part Mg in LaMg3 by Cu, the elastic constants C11 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 anisotropic 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 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.
Key words:first-principle calculations; elastic constant; ideal strength; mechanical properties; electronic structure
