Formation of Intermetallic Phases in Fe-Al Binary Cold Spray Thick Deposit

Thick Fe-Al deposits were produced by low-pressure cold spraying using heated air as the working gas. The coatings were isothermally annealed for two hours in Ar at temperatures from 250 °C to 750 °C. Changes in fracture behavior and microhardness were evaluated along with the microstructure and composition of newly formed phases. The results show that the evolution of intermetallic phases was driven by diffusion at temperatures above 550 °C. The new phases formed a hard skeleton that preserved the general shape of the samples during treatment despite the growth of external dimensions and porosity.