Orthorhombic metal carbide-borides MeC${}_2$B${}_{12}$ (Me=Mg, Ca, Sr) from first principles: structure, stability and mechanical properties

Abstract

First principle DFT simulations are employed to study structural and mechanical properties of orthorhombic B12-based metal carbide-borides. The simulations predict the existence of Ca- and Sr- based phases with the structure similar to that of experimentally observed earlier compound MeC${}_2$B${}_{12}$. Dynamical stability of both phases is demonstrated, and the phase MeC${}_2$B${}_{12}$ is found to be thermodynamically stable. According to simulations, Ca- and Sr- based phases have significantly enhanced mechanical characteristics, which suggest their potential application as superhard materials. Calculated shear and Young moduli of these phases are nearly 250 and 540 GPa, respectively, and estimated Vickers hardness is 45-55 GPa.

11 pages, 4 figures, 3 tables

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• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Necessary and Sufficient Elastic Stability Conditions in Various Crystal Systems
• Intrinsic Correlation between Hardness and Elasticity in Polycrystalline Materials and Bulk Metallic Glasses
• Mechanical properties of AlMgB14-related boron carbide structures. A first principle study

Cited by in corpus (1)

• Mechanical properties of B12-based orthorhombic metal carboborides. A first principle study