Promoting strength-ductility synergy by mitigating heterogeneity in precipitation-strengthened FCC/B2 dual-phase high-entropy alloy

This study introduces a novel heterogeneity-mitigating strategy to enhance the strength-ductility synergy in precipitation-strengthened FCC/B2 dual-phase high-entropy alloys (DP-HEAs), addressing the challenge of strain localization and interfacial cracking between phases. While traditional FCC/B2 DP-HEAs benefit from heterogeneous deformation-induced effects, increased strength in precipitation-strengthened FCC/B2 DP-HEAs often leads to premature failure due to strain localization. Traditional approaches, such as microstructure refinement and morphological regulation, often fall short, especially in alloys with significant phase volume fraction differences and precipitation. By employing precise microstructural regulation, the heterogeneity-mitigating strategy achieves a twofold increase in ductility and a significant enhancement in strength. The micro-digital image correlation technique elucidates the role of dual-phase heterogeneity in interfacial strain partitioning, while nanoindentation and simulations reveal the intrinsic link between reduced heterogeneity and improved deformation compatibility. This approach overcomes the limitations of existing methods, offering a new pathway for the synergistic enhancement of strength and ductility in precipitation-strengthened FCC/B2 DP-HEAs with differing phase properties and volume fractions.