Theory of the effects of substitutions on the phase stabilities of Ti1-xAlxN

We have performed ab initio studies of the effect of substitutions on the phase stabilities of Ti1-xAlxN, x=0-1. The nonmetal substitutions studied include B, C, O, and Si. Metal substitutions studied include Sc, Zr, V, Cr, and Mn. The main objective has been to suggest substitutions that increase the thermal stability of the NaCl structure of Ti1-xAlxN at high Al contents. From these extensive and consistent calculations, some possible avenues for such stabilization present themselves, among which substitution with nonmetal C and Si, and metal V, Cr, and Mn are found to be the most promising. (C) 2003 American Institute of Physics.