Integrating Diverse Strengtheners Empowers a Ferrous High-Entropy Alloy at Ambient and Elevated Temperatures

Abstract

The development of materials that exhibit enhanced strength-ductility synergy across a broad temperature spectrum is a non-stop pursuit for material scientists. It challenges the conventional paradigm of materials designed for optimal performance within a limited temperature range. In this study, we implement a combinational approach by integrating the high-entropy principles of a metastable Fe-based metallic matrix with negative mixing enthalpy strategies for intermetallic precipitates, alongside phase engineering techniques for multicomponent ceramic dispersions, to fabricate a novel multiphase high-entropy alloy with a nominal composition of Fe-28.2Ni-17Co-11Al-2.5Ta-0.5C-0.04B (at.%). The composite microstructural design leverages various strengthening mechanisms across scales, such as dislocation slip, deformation twinning, and martensite phase transformation at high strength levels, thereby achieving a remarkable tensile strength over 1.83 GPa and an exceptional tensile elongation of 20.6% at room temperature. Furthermore, it demonstrates an impressive yield strength of 583 MPa at 1073 K, substantially broadening its applicability at elevated temperatures compared to traditional ferrous alloys. The strategic integration of diverse deformation mechanisms through multiphase design not only enhances material performance under extreme conditions but also opens new avenues for the application of advanced materials in demanding environments.