Excellent tensile property and its mechanism in Al0.3CoCrFeNi high-entropy alloy via thermo-mechanical treatment

Al0.3CoCrFeNi is one of the widely studied high-entropy alloys (HEAs) due to the superior properties; however, its strength at room temperature is not satisfactory. The thermo-mechanical method was usually used to tune the mechanical property of materials. Here the as-cast Al0.3CoCrFeNi HEA was cold rolled and subsequently annealed for various times. The microstructural variation was characterized by X-ray diffraction, electron backscatter diffraction and transmission electron microscopy and the mechanical properties were estimated by microhardness and tension tests. It was found that the shorter annealing time led to a finer grain size and higher hardness. Besides, the yield strength of similar to 467 MPa, ultimate tensile strength of similar to 830 MPa and tensile elongation of similar to 48% were achieved in the thermo-mechanically processed alloy, which was comparable with or even a little higher than the previously reported data. The excellent combination of strength and ductility in this alloy was mainly ascribed to the combined action of residual dislocations, refined grains, and annealing and deformation twins in the dislocation motion. The calculated results of the contributions from different strengthening mechanisms to yield strength were well consistent with the experimental data. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Through thermo-mechanical processing, it was found that a shorter annealing time can enhance the hardness of the Al0.3CoCrFeNi alloy, achieving higher mechanical properties. The excellent combination of strength and ductility in the alloy is mainly attributed to the combined action of multiple strengthening mechanisms.