Microstructure and properties analysis of FeCoNiAlCu dual-phase high-entropy alloy coating by laser cladding

In this work, a new dual-phase high-entropy alloy (HEA) coating is successfully synthesized by laser cladding. XRD, SEM, TEM, EBSD, and TG-DSC are employed to investigate the microstructures and high-temperature stabilities. Simultaneously, under high-temperature friction and universal mechanical tester, the wear properties at 25 °C, 400 °C, and 800 °C and the mechanical properties at the compression speeds of 1 %, 2 %, and 3 % are explored. As indicated by the results, the FeCoNiAlCu HEA coating is composed of FCC phase with small angle grain boundaries and small size grains and BCC phase with HAGBs and large size grains. In terms of mechanical properties, FeCoNiAlCu HEA coating has good strength and toughness. When considering the fracture mechanism, it transfers gradually from a ductile fracture to a brittle fracture with increased compression speed. Besides, FeCoNiAlCu HEA coating maintains good stability at a high temperature of 764.2 °C. Meanwhile, the wear resistance and friction reduction of HEA coating are improved obviously at 800 °C. With the rise of temperature, the friction coefficient decreases gradually, the wear rate reduces, and the antifriction and wear resistance are enhanced.