Insights to electronic structures, elastic properties, fracture toughness, and thermal properties of M23C6 carbides

Abstract

Based on the successful applications of the first-principles calculations method in many fields, the electronic structures, elastic properties, fracture toughness, and thermal properties of M23C6 carbides are studied using first-principles calculation based on density functional theory (DFT) in this research. The results of cohesive energy and the formation enthalpy exhibit the thermodynamic stability of these M23C6 carbides. The electronic properties indicate that the bond of M23C6 carbides shows the mixture characteristic of metallic and covalent bonds. Polycrystalline elastic properties, hardness and fracture toughness show that these M23C6 carbides are ductile, tolerant to damage, and elastic anisotropic. The probable cleavage plane and slip system are (110) plane and {100} 〈100〉 for Ti23C6, V23C6, Cr23C6, and Co23C6, while that are (100) plane, {110} 〈110〉 for Mn23C6, Fe23C6 and Ni23C6. Moreover, lattice thermal conductivity and its dependence on temperature are discussed.