By using a theoretical model, the activation energy for the high-temperature plastic deformation of carbide single crystals was predicted as a function of the C/Ti ratio. It was found that the values of the activation energy at the critical resolved shear stress were lower than that for the lattice self-diffusivity of C; except when x was equal to 0.75. At this concentration, a peak (560kJ/mol) appeared in the activation energy. This was equal to about 75% of that for the lattice self-diffusion of Ti in TiCx. This behavior was attributed to a contraction of the so-called window, of Ti atoms, through which the C atoms diffused. It was suggested that the x-dependence of the activation energy could be explained if it were assumed that the diffusion of C and Ti atoms was coupled during deformation.

J.D.Muñoz, A.Arizmendi, A.Mendoza-Allende, J.A.Montemayor-Aldrete: Journal of Materials Science, 1997, 32[14], 3189-93