Influence of Rolling Deformation on the Microstructure and Mechanical Properties of Cocrfenial0.5 High-Entropy Alloys

Abstract

Herein, the effect of rolling deformation on the microstructure and mechanical properties of CoCrFeNiAl0.5 high-entropy alloys were systematically investigated. The phase structure of the alloys before and after rolling deformation are both FCC+BCC biphase structure. With the increase of rolling deformation, the dendrite phase of FCC structure deflected, and the inter-dendrite phase of BCC structure was stretched to form a fibrous deformed structure. The mechanical properties of CoCrFeNiAl0.5 high-entropy alloys were significantly improved after a large rolling deformation, and among them, the hardness and elastic modulus of 70% deformation (CR70) alloys are the largest, which are 9.0 GPa and 270.0 GPa, respectively; while the tensile strength Rm and the maximum elongation δ of 90% deformation (CR90) alloys are the highest, which are 1498.77 MPa and 2.82%, respectively. Under various rolling deformation, the fracture of the high-entropy alloys is 45°~50° oblique fracture and all show dimple shapes of varying depths, indicating that the fracture type is typically microporous aggregation fracture. Therefore, the CoCrFeNiAl0.5 high-entropy alloys have favorable comprehensive mechanical properties after rolling deformation, further to provide technical support for the engineering application of high-entropy alloys.

Keywords: CoCrFeNiAl0.5 high-entropy alloys, Rolling deformation, Microstructure, Mechanical properties, Deformation mechanism