Lamellar-structured low-cost FeMn0.7Ni0.6Cr0.4Al0.3 high entropy alloy with excellent tensile properties

High-performance structural materials with low cost are highly desirable yet challenging. Here we report a novel Co-free FeMn0.7Ni0.6Cr0.4Al0.3 high entropy alloy (HEA) possessing in situ-formed lamellar structure fabricated by a vacuum arc melting method. The alloy is composed of alternating disordered face centered cubic (FCC) lamellae and disordered body centered cubic (BCC) lamellae, with a few ordered BCC (B2) precipitates embedded in the FCC matrix and a high-density B2 precipitates embedded in the BCC matrix. The composite-like lamellar structure renders this as-cast alloy with extraordinary tensile properties with a yield strength of ∼635 MPa and an ultimate tensile strength of ∼1061 MPa, together with an elongation of ∼19.4% at room temperature, primarily ascribing to the lamellar boundary strengthening. This as-cast cost-effective FeMn0.7Ni0.6Cr0.4Al0.3 alloy with lamellar structure and outstanding tensile properties is highly suitable for manufacturing high-performance metallic products by direct casting.