Corrosion and tribological behavior of CoCrFeMoNi high-entropy alloys as a potential vascular implant material

The high-entropy CoCrFeMoNi alloy showcases remarkable strength, flexibility, and corrosion resistance. Consequently, it's anticipated to display exceptional surface degradation resistance in corrosive environments. This research examines the corrosion and tribocorrosion behavior of CoCrFeMoNi samples in different coldrolling and annealing stages. The tribological evaluations were conducted in Hank's physiological solution at room temperature, employing 1 and 2 N loads. The increased corrosion resistance of the cold-rolled samples could be attributed to their fine-grained microstructure and elevated hardness, particularly pronounced in samples with higher cold-roll levels. Reciprocally, increasing the annealing temperatures would lead to a decline in corrosion resistance. The tribological performance indicates that the stability and durability of the passive layer were compromised in the rolled samples. Nevertheless, the rapid reformation of the re-passive layer following wear demonstrates significant tribocorrosion resistance across all HEA samples. Simultaneously, the reprotective layer in the annealed samples exhibited greater resistance than the initial passivation due to the dualphase structure and stress induced by wear. These findings underscore the alloy's potential for biomedical applications such as vascular implants requiring a blend of strength, flexibility, corrosion, and tribocorrosion resistance, along with an extended operational lifespan.

Automated summary

The high-entropy CoCrFeMoNi alloy exhibits remarkable strength, flexibility, and corrosion resistance. This study investigates its corrosion and tribocorrosion behavior. The cold-rolled samples show enhanced corrosion resistance due to their fine-grained microstructure and elevated hardness. However, increasing annealing temperatures reduce the corrosion resistance. The tribological performance demonstrates significant tribocorrosion resistance in all high-entropy alloy samples, and the reprotective layer in the annealed samples exhibits higher resistance.