Polycrystalline pure Fe and Fe-12Cr alloy have been proton-irradiated to doses of 10(-3)-3 x 10(-1) dpa at room temperature and 523 K. Samples were mechanically tested in tension and transmission electron microscopy (TEM) was performed on the as-irradiated material as well as on the irradiated and deformed material. At room temperature, pure Fe presents an initial yield point, that increases with the dose, followed by a yield region, indicative of a localized deformation mode. The Fe-12Cr alloy shows the same behavior, but the irradiation amplifies the effects previously mentioned. No yield point or yield region appears after irradiation at 523 K. TEM observations of the irradiated material showed a high density of small defect clusters which increases with the dose. Defect-free channels are observed in Fe-12Cr irradiated and deformed at room temperature. Results of the present investigation are compared with neutron irradiation of similar materials. (C) 2000 Elsevier Science B.V. All rights reserved.