Novel methods of evaluating materials in extreme environments

Abstract

Three novel experiments were completed to investigate the difference in radiation response between production methods of Inconel 625. Production methods explored were the laser-powder bed fusion additive manufacturing method and the more conventional production method where samples were cut from a plate of wrought material. The experiments carried out aimed to further the understanding of how samples of this alloy, produced by AM methods, differ in radiation resistance from samples produced by conventional methods. The first experiment looked at the differences when subjected to a proton beam, while the other two experiments looked at the differences that resulted from neutron radiation environments. Differences in the effects of the irradiations on the hardness and microstructure were compared between the different manufacturing methods. The first experiment used the ion beam of a cyclotron to impart damage onto a metal target, then located that damage using nanoindentation. The second experiment used fast neutrons from a PET isotope production machine to irradiate metals for damage studies, proving that the technique yields measurable results even at low fluence irradiations. The third experiment used the neutron field in the University of Missouri Research Reactor to irradiate nanogram-scale flakes of metal and compare them to samples approximately nine orders of magnitude larger, on the order of a gram. These smaller samples were able to be analyzed sooner and were safer to handle while showing similar radiation response as compared to the larger samples.