b'situ tension and ductility testing. Coupling experimental studies with dislocation dynamics models, we will identify the approaches that provide consistent deformation mechanisms between the nano/micro-scale and macro-scale tests, from which we will suggest standard practices.This project utilizes a multiscale, integrated feedback loop between models and experiments, to ascertain the effects of key experi-ment parameters on mechanical properties. We focus on a ferritic Generation II FeCrAl alloy, under equivalent neutron and Fe 2+self-ion irradiation conditions. Macroscopic dogbone tensile specimens exposed to 15 displacements per atom (dpa) of neutron irradiation are available to the team in the necessary geometries, along with virgin material for ion irradiation. We use the irradiated microstructure to inform finite element and dislocation dynamics models, which are then used to respectively design and interpret the macro-scale and nano/micro-scale tensile and ductility tests.for in-reactor service, across allFigure 2. TEM in situ tensile testing Achieving consistent deformationDepartment of Energy-Nuclearresults from unirradiated and mechanisms will lead to establish- Energy programs. irradiated (7 dpa, 357C) C35M FeCrAl ment of standard practices forspecimens in 101101 oriented nano/micro-mechanical testing.Accomplishments: grains. Stress-strain curves show that Specimens of C35M and C37M haveirradiated specimens exhibit lower The primary project outcome,yield than unirradiated specimens, which is a set of recommendedbeen ion irradiated also to 7 dpawhich may be attributed to the size guidelines for nano/micro-scaleat 375C. We have characterizedeffect given the high number densities the as-received and ion irradiatedof dislocation loop and Cr-rich mechanical testing, will lead tomicrostructures using TEM, tonanophase separation defects in the unprecedented reductions in theirradiated material. Still-frames from time and cost to qualifying materialsreveal a high density of dislocationTEM in situ videos are shown upon loops and no voids. initial loading and at fracture2022|AFC ACCOMPLISHMENTS 35'