Mechanical properties of CoCrFeNiV high-entropy alloys with different Cu element contents under different strain rates

Abstract

In this study, the alloys used contained Co, Cr, Fe, Ni, and V as the primary elements, while 6%–10% Cu was used as the added element. The high-entropy alloys (HEAs) were made in an electric-arc vacuum furnace from which specimens in the form of cylinders with a 5-mm diameter and 5-mm length were fabricated. An XRD analysis revealed that alloys with 6% and 8% Cu had a single-phase FCC structure, and a weak BCC peak only appeared in the (110) direction in alloys with 10% Cu. A universal testing machine was used for testing at the strain rates of [Formula: see text][Formula: see text]s[Formula: see text], [Formula: see text][Formula: see text]s[Formula: see text], and [Formula: see text][Formula: see text]s[Formula: see text], and the high strain rate was tested using a split Hopkinson pressure bar (SHPB) under strain at 3000[Formula: see text]s[Formula: see text], 4000[Formula: see text]s[Formula: see text], and 5000[Formula: see text]s[Formula: see text], respectively. The specimens did not fracture during the quasi-static compression and dynamic impact tests, which displayed better ductility. The surface of the three alloys had extensive dendrites and non-equiaxed crystal structures. In an EDS composition analysis, the Cr and V elements were more frequently observed in the intergranular region than in the interdendritic region.