Effects of neutron irradiation to 63 dpa on the properties of various commercial copper alloys

High purity copper and six commercial copper alloys were neutron irradiated to 47 and 63 dpa at about 4500C in the FFTF. Immersion density measurements showed a wide range of swelling behavior after irradiation to 63 dpa. At one extreme was CuBe in the aged and tempered (AT) condition which had densified slightly. At the other extreme was 20% CW Cu-0.1% Ag which swelled over 45%. Electrical resistivity measurements of high-conductivity alloys followed trends similar to previously published results for the same alloys irradiated to 16 dpa. That is a continued reduction in conductivity with fluence which appears to relate to transmutation products and, somewhat, to void formation and defect cluster development. At 63 dpa, the electrical conductivity of zone-refined copper had decreased significantly. The reduction was to a value comparable with that of the irradiated Cu-A125-the Al2O3 dispersion strengthened alloy. Conversely, for the moderate conductivity alloy CuBe, the electrical conductivity was unaffected for irradiation greater than 16 dpa. These results of the irradiated material were compared with electrical conductivity of unirradiated alloys examined after aging for 10 000 h. The most irradiation resistent high-conductivity, high-strength copper alloy examined after 63 dpa is Cu-A125 followed by MZC. Cu-2.0Be, only a moderate-conductivity alloy, exhibits very consistent irradiation resistant properties. Thus, Cu-A125 and MZC appear to be acceptable candidates for high heat flux materials in fusion reactor applications. (orig.)