Heterogeneous lamella-structure-driven strengthening and wear resistance of high-entropy alloys

The development of materials that simultaneously exhibit high strength, ductility, and wear resistance remains a critical challenge for advanced engineering applications. In this work, significant efforts were devoted to designing a heterogeneous lamellar structure (HLS) composed of FCC-CoCrFeMnNi and BCC-FeCoNiAlSi 0.5 high-entropy alloys (HEAs) using powder metallurgy. Results reveal that CoCrFeMnNi HEA powder possesses a single-phase FCC structure, while the sintered alloy consists of FCC phase along with secondary Cr 3 C 2 precipitates. In contrast, the FeCoNiAlSi 0.5 HEA retains a single-phase BCC structure before and after sintering. Compared with their homogeneous counterparts, the HLS HEAs demonstrate a compressive yield strength of ∼1190 MPa and a plastic strain of 12.55%. The reasonable improvement in strength and plasticity is attributed to back-stress strengthening arising from mechanical incompatibility between FCC/BCC lamellae, which enhances strain hardening behavior. In addition, the HLS HEA shows a reduced friction coefficient of ∼0.2 and a lower wear rate of ∼3.065×10 −5 mm 3 /N·m relative to the constituent HEAs. These improvements are associated with the suppression of strain localization and the promotion of stable tribo-oxidation during sliding. Furthermore, finite element modeling simulations provide further insight into stress and strain partitioning as well as heterogeneous deformation mechanisms, which are consistent with experimental results. Nevertheless, this study demonstrates that the design of HLS HEAs is an effective strategy for simultaneously improving mechanical and tribological performance in advanced engineering applications.