Grain refinement usually makes the materials stronger, while ductility has a dramatic loss. Here, a superior tensile strength–ductility synergy in a fully recrystallized ultrafine-grained (UFG) Al_0.1CrFeCoNi with abundant annealing twins was achieved by cold rolling at room temperature and short-time annealing. The microstructure characterization using electron backscattered scattering diffraction demonstrates that abundant geometrically necessary dislocations (GNDs) gather around the grain boundaries and twin boundaries after tensile deformation. Although coarse-grained (CG) samples undergo a larger plastic deformation than UFG samples, the GND density decreases with grain size ranging from UFG to CG. Transmission electron microscopy results reveal that the annealing twin boundary, which effectively hinders the dislocation slip and stores dislocation in grain interior, and the activation of multiple deformation twins are responsible for the superior strength–ductility synergy and work hardening ability. In addition, the yield strength of fully recrystallized Al_0.1CrFeCoNi follows a Hall–Petch relationship (σ_y = 24 + 676 d^–1/2), where d takes into account both grain boundaries and annealing twin boundaries. The strengthening effects of grain boundaries and annealing twin boundaries were also evaluated separately.

晶粒细化通常使材料更坚固，而延展性则有显着损失。_{在这里，完全再结晶的超细晶粒 (UFG) Al 0.1}具有优异的拉伸强度 - 延展性协同作用通过室温冷轧和短时间退火获得具有大量退火孪晶的CrFeCoNi。使用电子背散射散射衍射的微观结构表征表明，在拉伸变形后，大量的几何必要位错 (GND) 聚集在晶界和孪晶界周围。尽管粗晶粒 (CG) 样品比 UFG 样品经历更大的塑性变形，但 GND 密度随着晶粒尺寸从 UFG 到 CG 的变化而降低。透射电子显微镜结果表明，有效阻碍位错滑移并在晶粒内部储存位错的退火孪晶界以及多次变形孪晶的激活是优异的强度-塑性协同作用和加工硬化能力的原因。此外，_0.1 CrFeCoNi遵循 Hall-Petch 关系 (σy ₌  24 + 676 d ^–1/2 )，其中d考虑了晶界和退火孪晶界。还分别评价了晶界和退火孪晶界的强化效果。