Abstract: The tri-metal Ti–Al–Nb composites were processed through three procedures: hot pressing, rolling, and hot pressing, followed by subsequent rolling. The fabricated composites were then subjected to annealing at 600, 625, and 650°C temperatures at different times. Microstructure observation at the interfaces reveals that the increase in plastic deformation strain significantly affects TiAl₃ intermetallic layers’ evolution and accelerates the layers’ growth. On the contrary, the amount of applied strain does not significantly affect the evolution of the NbAl₃ intermetallic layer thickness. It was also found that Al and Ti atoms’ diffusion has occurred throughout the TiAl₃ layer, but only Al atoms diffuse through the NbAl₃ layer. The slow growth rate of the NbAl₃ intermetallic layer is due to the lack of diffusion of Nb atoms and the high activation energy of Al atoms’ reaction with Nb atoms.