Study of thermal properties of TiCN by Debye Einstein model, Debye Grüneisen model and quasiharmonic approximation

Abstract

Thermodynamic properties of ternary ceramic TiCN are studied by first-principles calculation combined with the Debye Einstein model, which considers the contribution of 3n−3 optical frequencies at the Γ point; Debye Grüneisen model, which treats optical frequencies as acoustic ones; and quasiharmonic approximation(QHA), which is the most prevalent method in prediction of phonon dispersion and thermal properties. No imaginary frequency shows that TiCN has dynamic stability, and negative formation energy indicates the thermodynamic stability. Particularly, TiCN has low thermal expansion coefficient, which rises quickly firstly and then gradually as temperature rises. The study of bulk modulus shows that TiCN possess excellent resistance to the volume thermal deformation. For temperature effects of thermal expansion coefficient, heat capacity and entropy, the obtained results show that Debye Einstein model are apparently closer to the QHA at low temperatures. Our present results provide guideline for exploration of thermal properties of multicomponent materials.