International Journal of Physics | Vol. 13, No. 10, October 2022 | pp. 73–80
DOI: 10.46882/2022/IJP/000150
Research Article
Title: Elasticity Metrics and High-Pressure Structural Transitions in Ultra-Incompressible Niobium Diboride
Names of Authors: V. I. Morozov¹, P. J. O’Connor²
Authors’ Affiliations:
¹ Institute of High Pressure Physics, Russian Academy of Sciences, Troitsk, Russia
² Department of Civil and Environmental Engineering, University College Cork, Cork, Ireland
Abstract: Developing ultra-incompressible structural materials capable of operating under extreme mechanical stress is vital for specialized aerospace engineering and deep-earth simulation components. This paper investigates high-pressure elasticity metrics and monitors structural phase transitions in hexagonal niobium diboride (NbB₂) up to hydrostatic pressures of 160.0 GPa. We performed first-principles density functional theory computations within the generalized gradient approximation framework. At zero pressure, the calculated bulk modulus is B0 = 245.0 GPa, with an elastic pressure derivative value of B0' = 4.08, matching experimental diamond anvil cell measurements within a 1.2% margin. The single-crystal elastic constants (C11, C33, C44, C12, and C13) increase monotonically under uniform compression, satisfying all Born mechanical stability parameters across the entire pressure range. The directional compressibility paths reveal that the crystal c-axis displays exceptional stiffness due to short, covalent niobium-boron bonds. Electronic structure computations show a high density of states at the Fermi level, indicating that NbB₂ maintains its metallic profile under ultra-high pressures. These precise elastic records confirm the viability of transition metal borides as robust alternatives to conventional superhard ceramics.
Keywords: Niobium diboride; density functional theory; elastic constants; high pressure; structural stability; mechanical properties
Manuscript Timeline: Received: July 12, 2022; Revised: September 04, 2022; Accepted: September 22, 2022; Published: October 14, 2022
Citation: Morozov, V. I., & O’Connor, P. J. (2022). Elasticity Metrics and High-Pressure Structural Transitions in Ultra-Incompressible Niobium Diboride. International Journal of Physics, 13(10), 73–80.
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