Neutron irradiation damage in a precipitation-hardened aluminum alloy

JKS1E1A 6061 aluminum alloy target sleeve from the High Flux Isotope Reactor, originally in a precipitaJion-hardened condition, was examined for neutron radiation damage after exposure to a maximum fast fluence of 9.2 x 10 22 n/cm 2 (E > 0.1 MeV) and a thermal fluence of 1.2 X 10 23 n/cm 2 at 60 c C. Voids and a transmutation-produced silicon precipitate were found to cause about 1.1$ internal swelling; a .surfaceoxide scale contributed additional swelling.Irradiation-induced strength increases were measured at test temperatures in the range 25 to 200 c C and are accounted for in terms of the observed silicon precipitate and an associated dislocation structure.There was also,.aloss of ductility which was most severe at 200C, The fracture mode remained transgranular over the range of test temperatures.