Influence of irradiation damage on stress-assisted grain growth in ultrafine grained Au thin films using in situ transmission electron microscopy mechanical testing

This study explores the effects of irradiation damage levels on the mechanical properties and microstructural evolution of ultrafine grained Au thin films. Using quantitative in situ transmission electron microscopy mechanical testing, it was observed that the yield stress increased significantly, but only after a sufficiently high level of irradiation damage was reached, while ductility dropped significantly across all irradiated specimens. The results highlight grain boundaries as sinks for irradiation-induced defects, with mechanical loading further enhancing grain boundary migration and the absorption of smaller grains. More specifically, stress-induced grain growth resulted in regions cleared of irradiation defects, with more highly irradiated specimens showing limited areas cleared of defects due to the absence of smaller grains in the initial microstructure. This research provides insights into the interplay between irradiation damage, microstructural stability, and mechanical properties for ultrafine grained materials.