High-Temperature Oxidation Behavior and Grinding Performance of CoCrFeMnNi High-Entropy Alloy

Abstract

Herein, the mechanical properties, oxidation behavior, and processing performance of the CoCrFeNiMn high-entropy alloy are investigated using multiple characterization methods. The alloy exhibits a yield stress of 462 MPa, an ultimate tensile strength of 1037 MPa, and a fracture strain of 31.8% at room temperature. Oxidation tests reveal that the oxide layer consists of an outermost oxide layer and a Cr₂O₃ layer at both 1000 and 1200 °C. The Cr₂O₃ layer formed at 1000 °C is dense and continuous, whereas it transitions from continuous to discontinuous as the temperature increases to 1200 °C. Localized peeling of the oxide layer is observed at 1200 °C due to the diminished protective effect of the Cr₂O₃ layer and the increased stress in the oxide layer caused by the formation of multiple complex oxides. Grinding experiments indicate that both the grinding force and surface roughness increase as the load increases. Additionally, energy-dispersive X-ray spectroscopy results show that the oxygen content of particles at a 120 N is higher than at 60 and 90 N, suggesting an elevated grinding temperature at 120 N, which leads to the formation of bonded convex particles.