Mechanical anisotropy and Debye temperature in c-BN material

Abstract

2 dimensional dependence of mechanical moduli in cubic zincblende boron
nitride (c-BN) has been studied using the experimental Brillouin scattering
elastic constants Cij (C11 = 820 GPa, C12 = 190 GPa and C 44 = 480 GPa) of
the litterature (M. Grimsditch, E. S. Zouboulis, A. Polian, J. Appl. Phys. 76
(1994) 832). The linear compressibility, shear modulus, Young’s modulus
and Poisson’s ratio have been schematized in graphical representations.
The maximum value of the shear modulus, Gmax is 480 GPa, while its
minimum value Gmin is 315 GPa, which gives Gmax/ Gmin = 1.524, those of
the Young's modulus, Emax is 1028.6 GPa and Emin is 748.5 GPa, which
gives a ratio Emax/Emin = 1.374; while for the Poisson’s ratio υ, the maximum
value υmax is 0.236 and the minimum value υmin is − 0.02, which gives an
indefinite value (∞) for υmax/υmin.
Furthermore, we predict the Debye temperature ΘD of c-BN compound, it
is 1930.5 K from Siethoff’s formula and 2057.2 K from Blackman’s
expression, respectively.