Irradiation hardening and microstructural evolution und neutron and electron irradiation have been investigated for pure-Fe and Fe-Cu model alloys. Neutron and electron irradiations were performed in the Japan Material Test Reactor (JMTR) and with using Phodtron electron accelerator at about 290°C and 270±30°C, respectively. Irradiation hardening of pure-Fe and Fe-Cu model alloys is saturated at about 1 × 10-3 dpa in both the neutron and electron irradiation. Irradiation hardening recovered in two temperature ranges. The recovery in the lower temperature range depends on copper concentration and electron irradiation dose, while the recovery at a higher temperature range does not. Recovery behavior of the irradiation hardening suggests indirectly that copper atoms suppress the growth of interstitial clusters. The recovery behavior of positron lifetime does not coincide with that of the hardness, suggesting that the vacancy clusters are not the direct main factor controlling the hardening by matrix damages.