High-Pressure Elastic Moduli and Structural Stability of Ultra-Incompressible Tungsten Tetraboride

International Journal of Physics | Vol. 7, No. 6, June 2016 | pp. 41–48

DOI: 10.46882/2016/IJP/000074

Research Article

Title: High-Pressure Elastic Moduli and Structural Stability of Ultra-Incompressible Tungsten Tetraboride

Names of Authors: V. I. Morozov¹, K. A. Tanaka²

Authors’ Affiliations: ¹Institute of High Pressure Physics, Russian Academy of Sciences, Troitsk, Russia; ²Department of Physics, Tokyo Institute of Technology, Tokyo, Japan

Abstract: Designing ultra-incompressible structural materials capable of withstanding extreme mechanical stress is vital for industrial tooling and high-pressure research components. This paper examines the high-pressure elastic moduli and structural stability of orthorhombic tungsten tetraboride (WB4) up to hydrostatic pressures of 130.0 GPa. We performed first-principles density functional theory computations within the generalized gradient approximation framework. At zero pressure, the calculated bulk modulus is B0 = 328.0 GPa, with an elastic derivative value of B0' = 4.15. These results match experimental diamond anvil cell measurements within a 1.5% margin. The single-crystal elastic constants (C11, C22, C33, C44, C55, and C66) increase monotonically under compression, satisfying all Born mechanical stability conditions across the tested pressure range. The directional compressibility curves reveal that the crystal c-axis is significantly stiffer than the a-axis and b-axis, which is due to short, covalent tungsten-boron bonds aligned along the plane. The electronic structure calculations show a high density of states at the Fermi level, indicating that WB4 retains its metallic character under high pressure. These precise elastic profiles confirm the potential of transition metal borides as viable alternatives to diamond-based superhard materials.

Keywords: Tungsten tetraboride; density functional theory; elastic constants; high pressure; mechanical stability; directional compressibility

Manuscript Timeline: Received: February 15, 2016; Revised: April 12, 2016; Accepted: May 04, 2016; Published: June 15, 2016

Citation: Morozov, V. I., & Tanaka, K. A. (2016). High-Pressure Elastic Moduli and Structural Stability of Ultra-Incompressible Tungsten Tetraboride. International Journal of Physics, 7(6), 41–48.

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