SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2021, Vol. 40 ›› Issue (12): 315-322.DOI: 10.1016/j.cjche.2020.11.033

• Materials and Product Engineering • Previous Articles     Next Articles

Thermodynamic property of ternary compound MgCaSi: A study from ab initio Debye-Grüneisen model

Rui Wu1,2, Ya-Ping Wang1, Lin Shao1, Wei Wang1, Bi-Yu Tang1   

  1. 1. School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China;
    2. Institute of Biological Manufacturing Technology Co. Ltd, Guangxi Institute of Industrial Technology, Nanning 530022, China
  • Received:2020-09-30 Revised:2020-11-23 Online:2022-01-14 Published:2021-12-28
  • Contact: Bi-Yu Tang,E-mail:tangbiyu@gxu.edu.cn
  • Supported by:
    Authors gratefully acknowledge the support from Significant Project of Guangxi Scientific Foundation (2018GXNSFDA281010) and National Natural Science Foundation of China (51461002).

Thermodynamic property of ternary compound MgCaSi: A study from ab initio Debye-Grüneisen model

Rui Wu1,2, Ya-Ping Wang1, Lin Shao1, Wei Wang1, Bi-Yu Tang1   

  1. 1. School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China;
    2. Institute of Biological Manufacturing Technology Co. Ltd, Guangxi Institute of Industrial Technology, Nanning 530022, China
  • 通讯作者: Bi-Yu Tang,E-mail:tangbiyu@gxu.edu.cn
  • 基金资助:
    Authors gratefully acknowledge the support from Significant Project of Guangxi Scientific Foundation (2018GXNSFDA281010) and National Natural Science Foundation of China (51461002).

Abstract: The thermodynamic properties of MgCaSi and its mother phase Ca2Si are comparatively investigated from ab initio calculations and quasi-harmonic Debye-Grüneisen model. At 0 K, MgCaSi is more thermodynamically stable. Under high temperature, the advantage of higher thermodynamically stability of MgCaSi is reduced, originating from the less negative entropy contribution because the thermodynamic entropy of MgCaSi increases more slowly with temperature and the entropy values are slightly smaller. With increasing temperature, the anti-softening ability for MgCaSi is slightly smaller due to the slightly faster decrease trend of bulk modulus than that of Ca2Si, although the bulk modulus of MgCaSi is higher in the whole temperature range considered. The thermal expansion behaviors of both MgCaSi and Ca2Si exhibit similar increase trend, although thermal expansion coefficient of MgCaSi is slightly lower and the increases is slightly slower at lower temperature. The isochoric heat capacity and isobaric heat capacity of MgCaSi and Ca2Si rise nonlinearly with temperature, and both are close to the Dulong–Petit limit at high temperature due to the negligibly small electronic contribution. The Debye temperature of both phases decrease with increasing temperature, and the downtrend for MgCaSi is slightly faster. However, MgCaSi possess slightly higher Debye temperature, implying the stronger chemical bonds and higher thermal conductivity than the mother phase Ca2Si. The Grüneisen parameter of MgCaSi and Ca2Si increase slightly with temperature, the values of MgCaSi are slightly larger. The investigation of electronic structures shows that with substitution of partial Ca by Mg in Ca2Si, the stronger MgSi, MgCa and SiSi covalent bonds are formed, and plays a very significant role for the structural stability and mechanical properties.

Key words: MgCaSi alloys, Density functional theory, Thermodynamic properties, Structural stabilities, Quasi-harmonic Debye-Grüneisen model

摘要: The thermodynamic properties of MgCaSi and its mother phase Ca2Si are comparatively investigated from ab initio calculations and quasi-harmonic Debye-Grüneisen model. At 0 K, MgCaSi is more thermodynamically stable. Under high temperature, the advantage of higher thermodynamically stability of MgCaSi is reduced, originating from the less negative entropy contribution because the thermodynamic entropy of MgCaSi increases more slowly with temperature and the entropy values are slightly smaller. With increasing temperature, the anti-softening ability for MgCaSi is slightly smaller due to the slightly faster decrease trend of bulk modulus than that of Ca2Si, although the bulk modulus of MgCaSi is higher in the whole temperature range considered. The thermal expansion behaviors of both MgCaSi and Ca2Si exhibit similar increase trend, although thermal expansion coefficient of MgCaSi is slightly lower and the increases is slightly slower at lower temperature. The isochoric heat capacity and isobaric heat capacity of MgCaSi and Ca2Si rise nonlinearly with temperature, and both are close to the Dulong–Petit limit at high temperature due to the negligibly small electronic contribution. The Debye temperature of both phases decrease with increasing temperature, and the downtrend for MgCaSi is slightly faster. However, MgCaSi possess slightly higher Debye temperature, implying the stronger chemical bonds and higher thermal conductivity than the mother phase Ca2Si. The Grüneisen parameter of MgCaSi and Ca2Si increase slightly with temperature, the values of MgCaSi are slightly larger. The investigation of electronic structures shows that with substitution of partial Ca by Mg in Ca2Si, the stronger MgSi, MgCa and SiSi covalent bonds are formed, and plays a very significant role for the structural stability and mechanical properties.

关键词: MgCaSi alloys, Density functional theory, Thermodynamic properties, Structural stabilities, Quasi-harmonic Debye-Grüneisen model