Effects of heat treatments and neutron irradiation on microstructures and physical and mechanical properties of copper alloys

Tensile specimens of Cu-Al2O3, CuCrZr and CuNiBe alloys were given different heat treatments and then irradiated with fission neutrons at 250 degrees C to a dose level of similar or equal to 0.3 dpa. Both unirradiated and irradiated specimens were tensile tested at 250 degrees C. The microstructure and electrical resistivity were determined in the unirradiated as well as irradiated conditions. The post-deformation microstructure and fracture surfaces were also investigated, The main effect of the bonding thermal cycle heat treatment was a slight decrease in the strength of CuCrZr and CuNiBe alloys. The strength of CuAl-25, on the other hand, remained almost unaltered. The post-irradiation tests at 250 degrees C showed a severe loss of ductility in the case of CuNiBe alloy. The irradiated CuAl-25 and CuCrZr specimens, on the other hand, exhibited a reasonable amount of uniform elongation. The results are briefly discussed in terms of thermal and irradiation stability of precipitates and particles and irradiation-induced segregation, precipitation and recovery of dislocation microstructure. (C) 1997 Elsevier Science B.V.