A novel NbC/CrMnFeCoN₀.₈ high entropy alloy matrix composites with ultrastrength and ductility: Experiments and density function theory

Abstract

In this work, NbC particle-reinforced CrMnFeCoNi0.8 high-entropy alloys (HEAs) matrix composites were prepared by induction melting method. With increasing NbC content, the strength of the composites increases first and decreases afterwards, while the ductility decreases monotonically. The composite with 5 vol% NbC exhibits an excellent combination of yield strength (458.9 MPa), ultimate tensile strength (917.9 MPa), and ductility (29.0% elongation). The enhanced strength of the composite can be attributed to the synergy of various strengthening mechanisms, including dislocation strengthening, Orowan strengthening and load-bearing effect. Density functional theory (DFT) calculations revealed that the addition of NbC particles increases the value at Fermi level for individual elements in the HEA matrix, which provides support for improving mechanical properties of the NbC-reinforced composites.