Defeating creep embrittlement under high-stress levels through heterogeneous grain architecture in a L1₂-strengthened multicomponent alloy

L1₂-strengthened multicomponent alloys exhibit excellent mechanical properties over a wide temperature range. However, defeating the intermediate-temperature creep embrittlement is challenging. Herein, we demonstrated that the creep damage tolerance can be enhanced in a heterostructure consisting of high-density low-angle boundaries and disconnected high-angle grain boundaries. Our results show that the rearrangements of the preexisting dislocations coupled with the interactions between precipitates and various faults can be simultaneously activated in the heterostructured alloy, which helps to accommodate the cumulative strain for a prolonged creep life. This work provides a feasible route to optimize the creep rupture resistance under high-stress levels among precipitation-hardened polycrystalline alloy systems.