Neutron spectrum and transmutation effects on the radiation damage of copper alloys

Experimental results on the neutron spectrum effect on strength and ductility properties, transmutation rate and change in electric conductivity of copper-based alloys are presented in the paper. The analysis is based on the experimental study of radiation damage of pure copper, precipitation-hardened (PH) and dispersion-strengthened (DS) alloys, irradiated in the mixed spectrum reactor SM-2 and in the fast neutron spectrum reactor BOR-60 with the doses of (1-16) x 10(21) neutrons cm(-2). It is shown that accumulation rate of the transmutants (Ni, Zn and He) in the SM-2 reactor is higher than in the BOR-60 reactor, which can be attributed to a high power flux of thermal neutrons in the SM-2 reactor. This causes a significant reduction in electric resistivity and mechanical properties of copper-based alloys. The effect of irradiation dose and temperature upon DS and PH copper alloy characteristics is analyzed. A threshold softening temperature for PH alloys is shown to be 300 degrees C at a dose of 5 x 10(21) neutrons cm(-2) The mechanism of the spectrum effect on the shift of the threshold softening temperature of PH copper alloys is also considered. (C) 1997 Elsevier Science S.A.