Effect of anti-site point defects on the mechanical and thermodynamic properties of MgZn2, MgCu2 Laves phases: A first-principle study
Effect of anti-site point defects on the mechanical and thermodynamic properties of MgZn2, MgCu2 Laves phases: A first-principle study
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反位点缺陷对 MgZn2、MgCu2 Laves 相机械和热力学性能的影响：第一性原理研究
DOI：
10.1016/j.jssc.2018.04.001
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发表时间：
2018-07
影响因子：
3.3
通讯作者：
Jianquan Liang
中科院分区：
文献类型：
--
作者：
Shuo Wang;Yuhong Zhao;Hua Hou;Zhiqin Wen;Peilin Zhang;Jianquan Liang
采用第一性原理方法研究了反位点缺陷对MgZn 2和MgCu 2合金力学和热力学性能的影响.结果表明，Mg反位缺陷在Zn位或Cu位上起强化作用，但表现出更强的脆性。而Mg亚晶格上的Cu反位缺陷相则表现出韧性倾向。沿着Debye-Grüneisen模型预测了该体系的热力学性质，包括德拜温度、热膨胀系数、振动热容和振动熵。考虑到晶格振动和热电子激发的贡献，可以计算Helmholtz自由能F，表明由Mg在Zn或Cu位的占位引起的反位缺陷与无缺陷相相比是不稳定的。此外，还进一步讨论了电荷转移总量、整体电荷密度差和局部电荷密度差对力学性能的影响。
A theoretical investigation on the effect of anti-site point defects on mechanical and thermodynamic properties of MgZn2and MgCu2based on the first-principles calculations has been implemented. The results show that Mg anti-site defect on Zn or Cu site plays a reinforcing role, while exhibiting a more brittle behavior. However, the defect phase of Cu anti-sites on Mg sublattice shows a ductile tendency. The temperature-dependent thermodynamic properties are also predicted along with Debye-Grüneisen model including Debye temperature, thermal expansion coefficient and vibrational heat capacity as well as vibrational entropy. Taking into account the contribution of the lattice vibration and thermal electronic excitations, the Helmholtz free energyFcan be calculated, suggests that anti-site defects caused by the occupancy of Mg at the Zn or Cu site are thermodynamically unstable compared to the defect-free phases. In addition, the total amount of charge transfer, the overall and the local difference charge densities are further discussed to analyze the mechanism of mechanical properties.
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DOI：
10.1016/j.physb.2013.02.013
发表时间：
2013-05
期刊：
Physica B: Condensed Matter
影响因子：
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作者：
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