EN
In this work the characteristic radiation, emitted during interaction of medium energy (200 keV) ambient heavy ions (Ar) with Fe_{4}Co_{66}Si_{12}B_{14}Nb_{1}Mo_{2}Cu_{1} (VV-6025X) amorphous alloy, was measured in grazing incident-exit angle geometry and in time sequence, in order to determine dynamics of formation of subsurface region, damaged through implantation, sputtering and interface mixing. It was shown that structure and composition of surface is unstable against heavy ions irradiation due to preferential sputtering and implantation of ions, and recoils, and that the dynamics of such modification can be monitored in-situ with particle induced X-ray emission (PIXE) method.