Reduced graphene oxide (rGO) reinforced CoCrFeNiMn high entropy alloy: Microstructure, mechanical properties, and corrosion behavior

Abstract

The CoCrFeMnNi high entropy alloy (Cantor), and its variant incorporating 0.2 wt% reduced graphene oxide (rGO), denoted as Cantor + rGO, were successfully synthesized using mechanical alloying followed by spark plasma sintering. Comprehensive characterization utilizing FESEM, XRD, and TEM provided detailed insights into the microstructural features of the materials. The addition of rGO reduced crystallite size from 209 nm to 169 nm, promoted a uniform distribution of carbide phases of smaller size, and enhanced microhardness from 421.8 HV to 510 HV for Cantor and Cantor + rGO, respectively. The incorporation of rGO into the Cantor structure led to an increase in compressive yield strength (CYS) from 1100 MPa for Cantor to 1250 MPa for Cantor + rGO sample. A significant decrease in corrosion current density of samples from 6.1 ± 1.5 μA/cm2 for Cantor to 1.4 ± 0.9 μA/cm2 for Cantor + rGO was observed due to the addition of rGO reinforcement. Moreover, the pitting corrosion resistance was increased in rGO-reinforced Cantor, as revealed by cyclic polarization test. This research underscores the potential for utilizing rGO as a reinforcing agent to optimize the mechanical and corrosion resistance characteristics of HEAs, offering promising avenues for advanced materials in diverse applications.