First-Principles Investigations of Electronic Structures, Mechanical Properties, and Thermodynamic Characteristics of Scandium Carbide Compounds

Aiming to study the electronic structures, mechanical properties, and thermodynamic characteristics within framework of density function theory for scandium carbide (Sc x C y ) compounds, first-principles calculations were performed. The calculated cohesive energy and formation enthalpy indicate that the compounds have the thermodynamically stable structures. Their electronic characteristics indicate that ScC, Sc 2 C, Sc 2 C 3 , and Sc 3 C 4 present metallic character but Sc 4 C 3 presents semiconductor character. According to the stress-strain method, the elastic constants were calculated. In a framework of the Voigte-Reusse-Hill approximation, bulk modulus ( B ), shear modulus ( G ), Young’s modulus ( E ), Poisson’s ratio (σ), and Vickers hardness ( ) were analyzed. The largest value of B , G , E are found from Sc 2 C 3 . Both ScC and Sc 2 C 3 are ductile whereas other compounds are brittle. Mechanical anisotropy analysis indicates that Sc 2 C 3 has the highest anisotropy because its percent anisotropy A G (0.038) is the largest one. Furthermore, the relationship of thermodynamic properties such as specific heat capacity, entropy, Helmholtz free energy and internal energy with temperature were analyzed.