In the present work, the experimental study of the features of phase formation processes in preliminary mechanically activated powder mixture Ti+Al was conducted. The synthesis was realized in the thermal explosion mode with the use of microwave heating. It was established that in the case of a continuous transition from the fast heating mode (thermal explosion) to the high-temperature annealing regime the structural relaxation processes occurs. These processes lead to equalization of the phase composition in the volume of the mixture and formation of the almost single phase compound TiAl. At later stages of annealing, the transition to thermodynamic equilibrium state takes place. This process is accompanied by formation of compounds which are in equilibrium with each other at a given temperature.