Theoretical and experimental investigations on elastic properties of substoichiometric titanium nitrides: influence of lattice vacancies

Substoichiometric titanium nitrides have been synthesized by multiple energy ion implantation at the surface of pure titanium. Elastic properties have been studied by nanoindentation. Self consistent Full Potential Linear Muffin Tin Orbital (FP-LMTO) calculation with empty spheres in place of the missing nitrogen atoms gives the corresponding bulk modulus and lattice parameter values. The results, both experimentally and theoretically, show the same evolution of the lattice parameter and the bulk modulus, as a function of vacancy concentration. The agreement between experimental and theoretical values is discussed in relation with the vacancy effect.