Nature Materials, Published online: 03 August 2026; doi:10.1038/s41563-026-02702-7A hierarchically heterostructured high-entropy alloy combines bimodal core–shell grains, nanoprecipitates and oxide particles that remain stable up to 1,000 °C, delivering 2.2 GPa yield strength under high strain-rate loading without sacrificing impact toughness.