Effect of Proton Irradiation on Tensile Properties of Cu and a Cu-Cr-Zr Alloy

IN ORDER TO SIMULATE THE EFFECTS OF 14 MEV NEUTRON DAMAGE IN MATERIALS TO BE USED IN THE DIVERTOR OF A TOKAMAK FUSION REACTOR, IRRADIATION WAS UNDERTAKEN USING 18 MEV PROTONS INDUCED BY A CYCLOTRON. THE MATERIALS INVESTIGATED WERE OXYGEN FREE HIGH CONDUCTIVITY CU AND A CU-CR-ZR ALLOY FROM WHICH THIN MINIATURIZED SPECIMENS WERE PRODUCED FOR TENSILE TESTING AND MICROHARDNESS MEASUREMENTS. TESTING OF UNIRRADIATED MATERIAL DEMONSTRATED THAT AT SPECIMEN THICKNESSES BELOW 0.5 MM THE PRIMARY EFFECT OF DECREASING THE THICKNESS FURTHER WAS THAT OF LOWERING THE DUCTILITY, WHILST THE YIELD STRESS AND ULTIMATE TENSILE STRENGTH REMAINED UNCHANGED. IRRADIATION WAS CARRIED OUT AT 295 DEGREES UP TO A DAMAGE LEVEL OF 0.2 DPA. POST-IRRADIATION TESTING SHOWED THAT FOR ANNEALED OFHC CU A SOFTENING HAS OCCURRED. FOR THE CU-CR-ZR ALLOY IT WAS FOUND THAT THE STRENGTH DECREASED DURING IRRADIATION, THE FALL BEING APPROXIMATELY 50% AT 0.2 DPA.NA-NOT AVAILABL