Ultra-high strength and ductility of eutectic high-entropy alloy with duplex heterostructure at room and cryogenic temperatures

Abstract

• A duplex heterostructure with FCC/L1 2 and B2 phases in Ni 49 Fe 28 Al 17 V 6 eutectic high-entropy alloy was architected by thermal-mechanical process. • Ultra-high yield strength of ∼1877 MPa, ultra-high tensile strength of ∼2157 MPa and uniform elongation of ∼10 % were achieved at cryogenic temperature (77 K). • Such excellent cryogenic-temperature mechanical properties are mainly attributed to the hetero-deformation induced (HDI) hardening, and the strong interaction of deformation twins and high-density dislocations. Here, we architected a duplex heterostructure with FCC/L1 2 and B2 phases in Ni 49 Fe 28 Al 17 V 6 eutectic high-entropy alloy (EHEA) by thermal-mechanical process. Ultra-high yield strength of ∼1550 MPa, high tensile strength of ∼1772 MPa and good ductility of ∼16.5 % at room temperature (298 K) were exhibited. Particularly, ultra-high yield strength of ∼1877 MPa, ultra-high tensile strength of ∼2157 MPa and uniform elongation of ∼10 % were achieved at cryogenic temperature (77 K). Such excellent room-temperature mechanical properties are attributed to the hetero-deformation induced (HDI) hardening. Ultrahigh cryogenic-temperature strength originates from not only HDI hardening, but also the strong interaction of deformation twins and high-density dislocations.