Off-stoichiometry and molybdenum substitution effects on elastic moduli of B1-type titanium carbide.

B1-type MX ceramics are composed of transition metals (M) and C, N, and/or O (X) occupying the M and X sites, respectively, and having M-X nearest neighbor (NN) bonds and M-M and X-X next nearest neighbor (NNN) bonds. Substitution of the elements and the formation of structural vacancies in B1-type ceramics change the numbers and strengths of the bonds, leading to novel properties. The change in elastic modulus of off-stoichiometric TiC in equilibrium with a Ti-Mo solid solution phase was experimentally investigated based on the rule of mixtures from the Voigt model.