제1원리 계산을 이용한 IV, V족 전이금속 탄화물의 기계적 특성 및 이론강도 연구

Abstract

We investigated the elastic and mechanical properties of Groups IV and V transitionmetal carbides (TiC, VC, ZrC, NbC, HfC, and TaC) via first-principles calculations. We performedprecise convergence tests to obtain reliable results. The results for the equilibriumstructure of the carbide were in good agreement with previous results, indicating the reliabilityof the results. The Group IV carbides (TiC, ZrC, and HfC) exhibited a higher covalentbonding nature than the Group V carbides (VC, NbC, and TaC); thus, they had a higher brittlenessthan Group V carbides. Although the covalent bonding nature of the Group V carbideswas low, they exhibited higher elasticity and hardness than Group IV carbides, exceptfor HfC. In addition, the ideal strength of the carbides was investigated using highlydeformed models. TaC and ZrC had the highest and lowest ultimate tensile strengths,respectively.