Irradiation Aging of Aluminum Alloys

Abstract

In Hungary the VVRSZM-5 research reactor went into operation in 1959 and was operated continuously until 1986 without any failure. In 1986 the reactor was shut down for reconstruction. Since then the primary and secondary cooling circuits were dismantled and replaced. Many of these components were made from precipitation hardened aluminum alloy SZAV-1 similar in composition to AA6005 alloy. To increase knowledge about the aging of the mechanically loaded components few dismantled parts of the reactor were tested or samples were cut and stored for testing. In the meantime a new aluminum alloy for production of the main components of the reconstructed reactor has been developed and tested. This alloy, R-AlMg2.5 was produced on a clean aluminum base, and its weldment was carefully tested before usage. Sample heats of the SZAV-1 alloy (material of the dismantled reactor) and its weldments were irradiated together with the new R-AlMg2.5 (similar to AA5252) alloy and the properties of the materials compared. The results of the laboratory test series show a good correlation with the data obtained on the out-of-service material and weldments. The results shows that high dose irradiation (∼1024-1026 n/m2) fast neutron fluence, (E>1MeV) does not decrease the mechanical properties of the R-AlMg2.5 alloy and its weldments, while the toughness of the SZAV-1 weldments is reduced. The reconstructed reactor (called VVRSZM-10) had also a surveillance testing program, and surveillance results are verify the application of the irradiation resistant R-AlMg2.5 alloy.