Atomic-scale role of rare earth solution atoms in suppressing irradiation-induced void evolution in Mg-Y alloy

• The irradiation-induced void evolution of alloy at atomic-scale was firstly studied. • The growth of voids was hindered by the formation of clusters composed by yttrium element. • Voids undergo irregular evolution due to the pinning role of yttrium clusters. • The combination of HAADF and STEM could clearly recognize the distribution of yttrium atoms. The advancement of nuclear and aerospace technologies is contingent upon materials that exhibit lightweight properties, high strength, and superior radiation tolerance. Void formation within irradiated materials leads to significant degradation of their physical and mechanical characteristics. Alloying in metallic systems markedly improves resistance to irradiation-induced void swelling; however, a lack of direct experimental evidence has constrained the understanding of the specific roles played by alloying elements in void nucleation and evolution. In this study, we directly elucidate the influence of rare-earth solute atoms on irradiation-induced void evolution in a magnesium-yttrium (Mg-Y) alloy under electron irradiation through in situ scanning/transmission electron microscopy (S/TEM). By employing high-angle annular dark-field (HAADF) imaging and quantitative strain analysis, we demonstrate that Y clusters inhibit void growth via pinning and compressive strain fields, resulting in irregular void morphologies. These findings provide foundational insights into irradiation damage mechanisms in Mg-Y alloys and advance atomic-scale understanding pertinent to the design of materials for extreme radiation environments. (A) A HAADF detector collects the dark-field signal to form (B) an incoherent Z-contrast image; (B) show the irregular void evolution in Mg-Y alloy under in-situ electron irradiation; (C) show the schematic diagram of the mechanism of void nucleation, and evolution under in-situ electron irradiation of Mg-Y alloy.