Effect of bonding and bakeout thermal cycles on the properties of copper alloys irradiated at 350 degrees C

Screening experiments were carried out to determine the effect of bonding a nd bakeout thermal cycles on microstructure, mechanical properties and elec trical resistivity of the oxide dispersion strengthened (GlidCop, CuAl-25) and the precipitation hardened (CuCrZr, CuNiBe) copper alloys. Tensile spec imens were given heat treatments corresponding to solution anneal, prime-ag ing, bonding thermal treatment followed by re-aging and the reactor bakeout treatment. A number of specimens were irradiated at 350 degreesC to a dose level of similar or equal to0.3 dpa in the DR-3 reactor at Riso. Both unir radiated and irradiated specimens were tensile tested at 350 degreesC. The microstructure and electrical resistivity were determined in the unirradiat ed and irradiated conditions. The post-deformation microstructure and fract ure surfaces of unirradiated and irradiated specimens were examined. The ma in results are described and their salient features discussed. The most sig nificant effect of neutron irradiation is a severe loss of ductility in the case of CuNiBe alloys. (C) 2001 Elsevier Science B.V. All rights reserved.