Understanding the Fracture Failure Mechanism of WC Particle-Reinforced FeCoCrNiMn High-Entropy Alloy Coatings at 600 °C

Abstract

A detailed electron microscopy study was performed to clarify the fracture mechanism of WC particles reinforced with FeCoCrNiMn high-entropy alloy coatings at 600 °C. Large-sized fibers and elemental segregation formed in the coating, triggering high local stress in the matrix alloy and resulting in a low tensile strength of 150 MPa. High temperature promoted the homogenization process of elemental segregation, but also facilitated the dissolution of large-sized fibers, resulting in the growth of slim fibers and nanofibers. Both the structural homogenization and multi-scale fiber strengthening led to an enhanced tensile strength of 242 MPa at 600 °C. These current findings provide an understanding of the fracture mechanism of HEA/WC coatings during high-temperature exposure.