Transmission and post-nuclear-reaction emission Mössbauer spectroscopy were used for investigating radiation and deformation effects on Cr18Ni9Ti steel. The rolled foil was annealed for 2 h at 870 K and was irradiated with 30-MeV protons and 50-MeV alpha-particles up to doses of 5 × 10²¹ m⁻² on a liquid nitrogen cooled target. All transmission spectra are identical. In the case of proton irradiation the emission spectrum is analogous to the spectrum of the plastically deformed specimen. But after alpha-particle irradiation there is no magnetic splitting in the spectra. It is concluded that with plastic deformation and proton irradiation the same processes change the neighborhood of the resonant atoms.