Design strategy for high-strength FeCoCrNi-based high-entropy alloys: The role of lattice distortion in mechanical enhancement

This study addresses the critical demand for high-strength materials by exploring FeCoCrNi-based high-entropy alloys (HEAs) doped with Ti, Mn, Cu, and Mo, leveraging the principle of least resistance to dislocation motion and lattice distortion engineering. Investigating grain boundary and solid solution strengthening across grain sizes (100–200 μm) and doping atom concentrations ( x =0–1), the research identifies non-monotonic yield strength peaks: 1476 MPa ( x =0.312) for Ti, 872 MPa ( x =0.068) for Mn, 940 MPa ( x =0.17) for Cu, and 1070 MPa ( x =0.239) for Mo. Ti-doped HEAs exhibit the most significant solid solution strengthening due to pronounced lattice distortion, ranking Ti>Mo>Cu>Mn across the four HEA systems in terms of solid solution strengthening. The lattice distortion model aligns robustly with experimental data, validating its predictive accuracy. This synergistic strengthening approach enables tailored design, with Ti doping proving most effective, offering a predictive framework to optimize HEA mechanical properties for extreme-environment applications.