Superior radiation tolerance via reversible disordering-ordering transition of coherent superlattices.

Materials capable of sustaining high radiation doses at a high temperature are required for next-generation fission and future fusion energy. To date, however, even the most promising structural materials cannot withstand the demanded radiation environment due to irreversible radiation-driven microstructure degradation. Here we report a counterintuitive strategy to achieve exceptionally high radiation tolerance at high temperatures by enabling reversible local disordering-ordering transition of the introduced superlattice nanoprecipitates in metallic materials. As particularly demonstrated in martensitic steel containing a high density of B2-ordered superlattices, no void swelling was detected even after ultrahigh-dose radiation damage at 400-600 °C. The reordering process of the low-misfit superlattices in highly supersaturated matrices occurs through the short-range reshuffling of radiation-induced point defects and excess solutes right after rapid, ballistic disordering. This dynamic process stabilizes the microstructure, continuously promotes in situ defect recombination and efficiently prevents the capillary-driven long-range diffusion process. The strategy can be readily applied into other materials and pave the pathway for developing materials with high radiation tolerance.