A novel high-entropy alloy with desirable strength and ductility designed by multi-component substitution for traditional austenitic alloys

Developing advanced alloys with high strength and desirable ductility is always the demanding target for the engineering metallic community. Here two [(Al0.5Ti0.5)-(FeCoNi)12]Cr3 and [Cr-(FeCoNi)12]Cr2.5(Al0.25Ti0.25) high-entropy-alloy compositions are designed using a cluster-plus-glue-atom model and their bridges with the traditional austenite steels are established. After thermomechanical treatment, the as-aged Al0.5Ti0.5 HEA with many L12 nano-precipitates (i.e. volume fraction of 30.35 % and average precipitate size of 43.28 nm) uniformly distributed in FCC matrix shows a high ultimate tensile strength of 1356.5 MPa and a sufficient ductility of 34.9 %, which mechanical properties are more outstanding than that of single-phase counterparts. The yield -strength increment is mainly contributed by the strengthening of coherent nano-L12 precipitates. Also, the nano-L12 precipitates with tiny lattice strain and superior strength-ductility combination decrease the local stress concentration, further guaranteeing the ductility of as-aged Al0.5Ti0.5 HEA. The above findings provide a reference for the development of high-performance engineering HEAs.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Two high-entropy-alloy compositions [(Al0.5Ti0.5)-(FeCoNi)12]Cr3 and [Cr-(FeCoNi)12]Cr2.5(Al0.25Ti0.25) were designed and bridges with traditional austenite steels were established. The thermomechanically treated Al0.5Ti0.5 HEA exhibited a uniform distribution of L12 nano-precipitates, resulting in a high ultimate tensile strength of 1356.5 MPa and a suitable ductility of 34.9%. The strengthening of coherent nano-L12 precipitates contributed to the increase in yield strength, while the nano-L12 precipitates with tiny lattice strain and superior strength-ductility combination reduced local stress concentration and ensured ductility.