International Journal of Physics | Vol. 9, No. 12, December 2018 | pp. 89–96
DOI: 10.46882/2018/IJP/000104
Research Article
Title: Elasticity Metrics and High-Pressure Structural Transitions in Ultra-Incompressible Hafnium Diboride
Names of Authors: V. I. Morozov¹, P. J. O’Connor²
Authors’ Affiliations: ¹Institute of High Pressure Physics, Russian Academy of Sciences, Troitsk, Russia; ²Department 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 hafnium diboride (HfB²) 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 = 252.0 GPa, with an elastic pressure derivative value of B0' = 4.05, 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 hafnium-boron bonds. Electronic structure computations show a high density of states at the Fermi level, indicating that HfB² 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: Hafnium diboride; density functional theory; elastic constants; high pressure; structural stability; mechanical properties
Manuscript Timeline: Received: August 19, 2018; Revised: October 02, 2018; Accepted: October 28, 2018; Published: December 14, 2018
Citation: Morozov, V. I., & O’Connor, P. J. (2018). Elasticity Metrics and High-Pressure Structural Transitions in Ultra-Incompressible Hafnium Diboride. International Journal of Physics, 9(12), 89–96.
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