Defect evolution in heavy ion irradiated nanotwinned Cu with nanovoids

Epitaxial nanotwinned Cu film with abundant nanovoids surrounding domain boundaries was subjected to Kr⁺⁺ ion irradiation inside a transmission electron microscope at various dose rates. Irradiation-induced defect clusters distributed preferentially near domain boundaries during the early stage of radiation. Meanwhile, the pre-existing nanovoids continuously shrank. This study suggests that the defect network enabled by the unique combination of nanotwins and nanovoids may significantly enhance the radiation tolerance of metallic materials.