›› 2014, Vol. 23 ›› Issue (9): 96201-096201.doi: 10.1088/1674-1056/23/9/096201

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

Anisotropy of elasticity and minimum thermal conductivity of monocrystal M4AlC3 (M=Ti, Zr, Hf)

丁艾玲, 李春梅, 王瑨, 敖靖, 李凤, 陈志谦   

  1. Faculty of Materials and Energy, Southwest University, Chongqing 400715, China
  • 收稿日期:2013-11-14 修回日期:2014-02-24 出版日期:2014-09-15 发布日期:2014-09-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 51171156), CSTC2012GGYS5001, and CSTC2013JCYJYS5002.

Anisotropy of elasticity and minimum thermal conductivity of monocrystal M4AlC3 (M=Ti, Zr, Hf)

Ding Ai-Ling (丁艾玲), Li Chun-Mei (李春梅), Wang Jin (王瑨), Ao Jing (敖靖), Li Feng (李凤), Chen Zhi-Qian (陈志谦)   

  1. Faculty of Materials and Energy, Southwest University, Chongqing 400715, China
  • Received:2013-11-14 Revised:2014-02-24 Online:2014-09-15 Published:2014-09-15
  • Contact: Chen Zhi-Qian E-mail:chen_zq@swu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 51171156), CSTC2012GGYS5001, and CSTC2013JCYJYS5002.

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摘要： The elastic constants, elastic anisotropy index, and anisotropic fractional ratios of Ti4AlC3, Zr4AlC3, and Hf4AlC3 are studied by using a plane wave method based on density functional theory. All compounds are characterized by the elastic anisotropy index. The bond length, population, and hardness of the three compounds are calculated. The degrees of hardness are then compared. The minimum thermal conductivity at high temperature limitation in the propagation direction of [0001] (0001) is calculated by the acoustic wave velocity, which indicates that the thermal conductivity is also anisotropic. Finally, the electronic structures of the compounds are analyzed numerically. We show that the bonding of the M4AlC3 lattice exhibits mixed properties of covalent bonding, ionic bonding, and metallic bonding. Moreover, no energy gap is observed at the Fermi level, indicating that various compounds exhibit metallic conductivity at the ground state.

关键词: elastic property, anisotropy, thermal conductivity, electronic structure

Abstract: The elastic constants, elastic anisotropy index, and anisotropic fractional ratios of Ti4AlC3, Zr4AlC3, and Hf4AlC3 are studied by using a plane wave method based on density functional theory. All compounds are characterized by the elastic anisotropy index. The bond length, population, and hardness of the three compounds are calculated. The degrees of hardness are then compared. The minimum thermal conductivity at high temperature limitation in the propagation direction of [0001] (0001) is calculated by the acoustic wave velocity, which indicates that the thermal conductivity is also anisotropic. Finally, the electronic structures of the compounds are analyzed numerically. We show that the bonding of the M4AlC3 lattice exhibits mixed properties of covalent bonding, ionic bonding, and metallic bonding. Moreover, no energy gap is observed at the Fermi level, indicating that various compounds exhibit metallic conductivity at the ground state.

Key words: elastic property, anisotropy, thermal conductivity, electronic structure

中图分类号:  (Elasticity)

  • 62.20.D-
71.15.Mb (Density functional theory, local density approximation, gradient and other corrections) 74.25.Bt (Thermodynamic properties) 71.20.-b (Electron density of states and band structure of crystalline solids)