Investigations on Inconel 718 irradiated with 800 MeV protons

In spallation sources, the neutrons (utilized as probes for condensed matte r research or for inducing nuclear transmutations) are generated by protons of around 1 GeV energy which cause spallation of the nuclei in a heavy met al target. The beam powers of the proposed future facilities are in the ran ge of 1 to several 10 MW and the corresponding high particle fluxes make ra diation damage the crucial effect for the lifetime of target structural mat erials in or close to the proton beam. In order to establish a database on spallation-relevant radiation effects, post-irradiation investigations of c omponents of spent targets from operating medium power sources are being pe rformed. Were we report first results on Inconel 718 irradiated in LAMPF up to a fluence of 3 x 10(25) p/m(2). Microhardness and bending tests togethe r with SEM and TEM investigations show a considerable degradation of the me chanical properties of the material requiring additional highly controlled tests, now underway, to determine fracture toughness and tensile properties as a function of dose. (C) 1999 Published by Elsevier Science B.V. All rig hts reserved.