Hafnium Carbide: Prediction of Crystalline Structures and Investigation of Mechanical Properties

Hafnium carbide (HfC) is a refractory compound known for its exceptional mechanical, thermal, and electrical properties. This compound has gained significant attention in materials science and engineering due to its high melting point, extreme hardness, and excellent thermal stability. This study presents crystal structure prediction via energy landscape explorations of pristine hafnium carbide supplemented by data mining. Apart from the well-known equilibrium rock salt phase, we predict eight new polymorphs of HfC. The predicted HfC phases appear in the energy landscape with known structure types such as the WC type, NiAs type, 5-5 type, sphalerite (ZnS) type, TlI type, and CsCl type; in addition, we predict two new structure types denoted as ortho_HfC and HfC_polytype, respectively. Moreover, we have investigated the structural characteristics and mechanical properties of hafnium carbide at the DFT level of computation, which opens diverse applications in various technological domains.