Laser deposited Fe-Ag alloys exhibit a supersaturation of the Fe(Ag) solid solution of up to 13 at.% Ag and an unusual lattice expansion in the growth direction. The relaxation process, grain coarsening, decomposition and mixing processes occurring during 350 keV Ar + irradiation at 77 K in these alloys were studied by X-ray diffraction. Depending on the original state of the samples, different processes dominate, but always lead to the same dynamic phase equilibrium under irradiation.