An arc-melted eutectic medium-entropy alloy with superior strength-ductility synergies at room and cryogenic temperatures

Abstract

The cryogenic compressive mechanical properties of eutectic multi-principal alloys have rarely been reported. In this work, the superior fracture strength-fracture strain synergies at room and liquid nitrogen temperatures (RT and LNT) of the arc-melted Cr50Co25Ni25 eutectic medium-entropy alloy were found. These values were 1917 MPa and 39.1 % at RT, along with 1990 MPa and 26.1 % at LNT. The reduction of ductility at LNT was primarily attributed to the inferior deformation capability of the BCC phase containing HCP phase. The fracture mechanisms were dominated by ductile fracture of the FCC phase and brittle fracture of the BCC phase at both temperatures, while dislocation pile-ups and stacking faults were responsible for the deformation mechanisms