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Combining high strength and good ductility is highly-desired yet challenging for conventional structural materials. Newly emerging concentrated multi-component alloys with face-centered-cubic structure provide an ultra-ductile matrix, and the precipitation hardening based on these alloys provides a very effective way to achieve a superior strength-ductility combination. Here, we report a high-strength CoCrNi-based medium-entropy alloy hardened by nanoscale L1₂-(Ni, Co, Cr)₃(Ti, Al)-type particles with mixing heterogeneous and homogeneous precipitation behaviors. Compared to the single-phase CoCrNi medium-entropy alloy, the yield strength and the tensile strength of the precipitation-strengthened CoCrNi medium-entropy alloy were increased by ∼70% to ∼750 MPa and ∼44% to ∼1.3 GPa, respectively, whereas a good ductility, ∼45%, was still achieved. The underlying deformation micro-mechanisms …