Dresden 2026 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 19: Poster Session

MM 19.34: Poster

Tuesday, March 10, 2026, 18:00–20:00, P5

The vacancy effect to the mechanical properties of high entropy borides — •Nebahat Bulut¹, Inna Plyushchay², Anna Pliushchai¹, and Sibylle Gemming¹ — ¹Institute of Physics, TU Chemnitz — ²Institute of Physics, National Taras Shevchenko University of Kyiv, Ukraine

High entropy transition metal diborides (HETMB₂) present complex lattice distortions that strongly influence their mechanical properties. These distortions are the result of atomic mismatch, metal-boron site vacancies, and strong covalent/ionic bonding. The randomly disordered structures of HETMB₂ are constructed with equimolar metal atom ratios to obtain the elastic stiffness tensors. Small strains are applied to the equilibrium unit cell to calculate the elastic response by performing first principles calculations using Quantum Espresso. Understanding the influence of lattice distortion on mechanical properties, we introduce distortion parameters which show the vacancy effect of different transition metal atoms. The distortion parameters were quantified based on the interatomic distances of nearest neighbor bond lengths. Mechanical stability and elastic anisotropy of HETMB₂ were analyzed as function of configurational disorder. It is discussed how the lattice distortions modify the Peierls barrier for dislocation motion.

Keywords: density functional theory; high entropy borides; configurational disorder; lattice distortion; dislocation motion