Enhancing mechanical properties of Al0.25CoCrFeNi high-entropy alloy via cold rolling and subsequent annealing

Abstract

The influence of simple thermo-mechanical processing such as cold rolling and subsequent annealing on the microstructure and mechanical properties of the single phase Al0·25CoCrFeNi high-entropy alloy is systematically investigated. Experimental results obtained from ten different processing parameters indicate that the microstructure and mechanical properties of the alloy can be comprehensively tuned in a wide range. The grain size can be reduced from hundreds of micrometer size to several tens micrometer size, and the yield and tensile strength can be enhanced from 173 MPa to 425 MPa–1050 MPa and 1160 MPa, respectively, while the alloy still owns large tensile ductility above 10%. Based on detailed microstructure analysis, the strength mechanism is shown to be related with both the refined grain size, nanoscale precipitation in the grain boundaries and recrystallized grains. This research shows that with simple multistep cold rolling and annealing, the mechanical properties of face-centered-cubic single phase high-entropy alloy can be highly tailored for different engineering applications.