Dispersion strengthened (CuAl25) and precipitation hardened (CuCrZr) copper alloys are being considered as candidate materials for the first wall and divertor components of ITER. In the present work, the tensile and fracture resistance properties of CuAl25 and CuCrZr alloys and their joints with 316LN stainless steel have been studied in the unirradiated and neutron irradiated conditions. The joints were produced by hot isostatic pressing (HIP) at 960°C for 3 hours at a pressure of 120 MPa. Test specimens of the base materials CuAl25 and CuCrZr alloys and of the joints (CuCrZr / 316LN and CuAl25 / 316LN) were irradiated with fission neutrons in the DR-3 reactor at Risø in the temperature range from 50°C to 350°C to a displacement dose level of about 0.3 dpa (NRT). Tensile specimens of these alloys were tested at temperatures in the range of 50°C to 350°C. Fracture resistance curves were determined using three point bend tests on specimens of the base materials and of the joints. Tensile and fracture toughness results, together with the metallography of the joints will be presented. Implications of these results and the deformation mechanisms will be briefly discussed.