Cold sprayed AA2024/Al ₂ O ₃ cermet coatings: evaluating cohesiveness and tribological performance with varying reinforcement levels

Alumina-reinforced AA2024 metal matrix composite (MMC) coatings were deposited on AZ31 magnesium alloy substrates by the cold spray (CS) method, with different alumina volume fractions of 20, 35, 50, and 65 vol.%. This study investigates the influence of alumina reinforcement on the microhardness, internal cohesion, and tribological performance of the MMC coatings. Experimental observations indicate that elevated alumina content increases the plastic deformation of AA2024 particles and improves the microhardness of the coatings. The addition of alumina increases the internal cohesive strength of the MMC coating; however, at high reinforcement levels, this strength degrades primarily due to reduced effective contact between metallic particles caused by excessive ceramic material. Therefore, the tribological research verifies that both the presence and increasing concentration of alumina particles have a strong impact on the wear behaviour of the AA2024/alumina MMC coatings deposited on AZ31 substrates.