Samples of Fe81B13.5Si3.5C2 metallic glass were irradiated with a pulsed excimer laser (λ=308 nm, τ=10 ns), with a high-energy electron beam (W=7 MeV), and with low-energy electron beams (W=30 and 50 keV). Irradiation-driven changes in the magnetic anisotropy and phase equilibrium of alloy samples were studied by Mössbauer spectroscopy and scanning electron microscopy. Pulsed-excimer-laser irradiation was found to induce controlled magnetic anisotropy without onset of bulk crystallization in the Fe81B13.5Si3.5C2 amorphous system. High-energy electron-beam irradiation determined an out-of-plane magnetic anisotropy due to changes in the chemical short-range order. Low-energy electron-beam irradiation resulted in the formation of crystalline regions, in which α-Fe, Fe-Si, Fe3B, Fe2B, and clusters of γ-Fe were identified. Interpretation of these results is given in terms of radiation-enhanced diffusion.