Vapor-deposited Zr-Fe multilayered thin films with different modulation were either irradiated with 300 keV Kr ions at temperatures from 25 K to 623 K to fluences up to 2x10¹⁶ cm^-2, or simply annealed at 773 K and studied in-situ in the Intermediate Voltage Electron Microscope at Argonne National Laboratory. The kinetics of ion beam mixing (IBM) and solid-state reaction (SSR) were followed by monitoring their diffraction patterns. In the case of IBM, two multilayers with 50-50 composition were examined, one with wavelength 270 Å ( Å), and another of wavelength 105 Å ( Å). During irradiation, the Zr and Fe rings weakened and an amorphous phase formed that increased with fluence. A unique steady state in the phase transformations was eventually reached for all temperatures studied, containing mostly amorphous Zr-Fe and some remnant hcp-Zr and bcc Fe; the dose to full reaction decreased with temperature and increased with wavelength of the layers.For the annealing experiments, the multilayers with composition 50 at.% reached a steady state similar to the IBM case, regardless of the wavelength. However, in Fe-rich films (55%at.Fe) different reaction products appeared depending on the wavelength: the intermetallic compounds ZrFe₂ and Zr₃Fe were formed in films with wavelength 250 Å ( Å), while an amorphous phase was observed in films with wavelength 150 Å ( Å). The results are discussed in terms of previous IBM and SSR experiments in the Zr-Fe system, and of the existing models for both processes.

*This work was supported by NSF Grant No. INT-9503934, and by CNPq.