Recent progress in analysis of strain-induced phenomena in irradiated metallic materials and advanced alloys using SEM-EBSD in-situ tensile testing

Abstract

In-situ mechanical testing in a scanning electron microscope (SEM) equipped with an electron backscatter diffraction (EBSD) system has quickly gained popularity, particularly because of its rich experimental outcomes. In this work, the advantages and challenges of this approach are systemized and critically discussed in relation to testing irradiated metallic materials and novel materials in development. Key observations and experimental results are evaluated for irradiated austenitic stainless steels, an additively manufactured (AM) 316 stainless steel, and a modern accident-tolerant FeCrAl alloy. Various deformation mechanisms are discussed using experimental EBSD datasets, including dislocation channeling in irradiated alloys, strain localization, lattice rotation, texture development, twinning, phase instability, and microfracture events. Several rare strain-induced phenomena are described, such as grain boundary dissolution in FeCrAl alloy and twinning boundary migration in AM 316 stainless steel. These results demonstrate the advantages and capability of EBSD-assisted experiments to inform assessment and understanding of the complexity of deformation processes at different microstructure scales. Some challenges and impediments associated with this approach are also discussed, along with recommendations for future research advancements.