Effect of nonstoichiometry on anisotropy of elastic properties of disordered cubic zirconium carbide ZrCy

Abstract

The elastic constants c11, c12, c44 are determined for the first time as functions of the carbon content y in the homogeneity region ZrC0.60 - ZrC1.00 of nonstoichiometric disordered cubic ZrCy zirconium carbide. It is established that the elastic stiffness constants cij of disordered ZrCy carbide decrease with an increase in the defectiveness of the carbon sublattice of zirconium carbide. An increase in the deviation of the ZrCy composition from stoichiometry leads to a slight decrease in the anisotropy of the elastic properties. The elastic properties of zirconium carbide are anisotropic, since they change depending on the crystallographic direction [hkl] due to differences in the arrangement of atoms and interatomic bonds in various directions. It is found that the values of elastic moduli depend on the crystallographic direction [hkl], and the maximum and minimum the Young's moduli are observed in the [001], [010], [100] or [±1 ± 1 ± 1] directions of cubic ZrCy carbide, respectively. Small changes in the elastic characteristics of ZrCy depending on the [hkl] direction indicate a weak elastic anisotropy of cubic zirconium carbide. It is shown that the calculated Vickers hardness and Debye temperature of polycrystalline disordered cubic ZrCy carbide increase non-linearly with increasing relative carbon content y.