Mechanical and thermodynamic properties of rare-earth-based Ni intermetallic compounds crystallized in the C15b structure: an Ab-initio study

This study investigates the mechanical properties and structural and thermodynamic stabilities of RENi5 compounds (RE: rare earth metals, with RE = Y, La, and Gd) in the AuBe5 (C15b) structure. Intermetallics of this type have potential applications in hydrogen battery technology, but their properties are not well understood. Using first-principles calculations, we calculated the mechanical properties, including the shear modulus, Young's modulus, bulk modulus, Poisson's ratio, Vickers hardness, and ductility of these compounds. Our calculations revealed that these compounds are both mechanically and thermodynamically stable. Additionally, our results suggest that all compounds are ductile. The YNi5 compound has the highest Debye temperature, indicating greater covalent Y-Ni bonds and greater hardness. We analyzed these findings with respect to the electronic structure of the compounds by calculating the density of states (DOS) and charge density distribution. These insights into the mechanical, thermodynamic, and electronic properties of RENi5 intermetallics can inform the design and development of novel materials with improved properties in hydrogen batteries, mechanical applications or other related fields.