Microstructure characterization of AlCrFeCoNi high-entropy alloy coating on Inconel 718 by electrospark deposition

Recent scientific advancements in the field of high entropy alloys have sparked significant interest due to their exceptional performance across diverse environments. These properties are particularly valuable in surface protection engineering, where the selection of appropriate coating materials can profoundly impact the cost and properties of high-performance components. Consequently, understanding their compatibility with conventional engineering alloys is crucial. This study presents a detailed microstructural analysis of as-deposited and heat-treated AlCrFeCoNi HEA coatings on Inconel 718 substrate, fabricated via electrospark deposition. The as-deposited coatings exhibited cellular grains predominantly composed of the BCC phase, showing minimal elemental segregation. Subsequent heat treatment induced FCC and σ precipitate formation in the coatings, leading to noticeable elemental and phase segregation. Comprehensive characterization using X-ray diffraction, nano-indentation, and microhardness testing investigate the metallurgical and mechanical properties of the fabricated coatings. Wear resistance tests demonstrated that HEA-based coatings hold promise for enhancing surface wear resistance.