International Journal of Physics | Vol. 4, No. 5, May 2013 | pp. 33–40
DOI: 10.46882/2013/IJP/000037
Research Article
Title: High-Pressure Mechanical Stability and Elastic Anisotropy of Advanced Transition Metal Diborides
Names of Authors: Y. V. Petrov¹, E. M. Gallagher²
Authors’ Affiliations: ¹Department of Theoretical Physics, Saint Petersburg State University, Saint Petersburg 199034, Russia; ²School of Physics, Trinity College Dublin, Dublin 2, Ireland
Abstract: Transition metal diborides are highly valued for their exceptional hardness, high melting points, and electrical conductivity under extreme operating conditions. This investigation evaluates the high-pressure mechanical stability and elastic anisotropy of titanium diboride (TiB2) and zirconium diboride (ZrB2). We performed first-principles density functional theory calculations using the generalized gradient approximation up to hydrostatic pressures of 100.0 GPa. At zero pressure, the calculated bulk modulus of TiB2 is B0 = 242.0 GPa, which closely matches experimental diamond anvil cell measurements within a 1.2% margin. As the pressure scales upward, the single-crystal elastic constants (C11, C33, C44, C12, and C13) increase linearly. Both materials strictly satisfy the generalized Born stability criteria across the entire pressure range, demonstrating robust mechanical integrity. We quantified the degree of elastic anisotropy using the universal anisotropy index (AU). The calculations show that ZrB2 exhibits a higher level of shear anisotropy compared to TiB2, with its index increasing from 0.15 to 0.38 at 100.0 GPa. This behavior indicates that ZrB2 is more susceptible to microcrack propagation along the basal plane under high shear strain. These precise elastic parameters offer valuable data for designing ultra-high-temperature ceramics for aerospace applications.
Keywords: Transition metal diborides; density functional theory; elastic constants; high pressure; mechanical stability; elastic anisotropy
Manuscript Timeline: Received: February 11, 2013; Revised: March 24, 2013; Accepted: April 10, 2013; Published: May 16, 2013
Citation: Petrov, Y. V., & Gallagher, E. M. (2013). High-Pressure Mechanical Stability and Elastic Anisotropy of Advanced Transition Metal Diborides. International Journal of Physics, 4(5), 33–40.
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