Effect of higher deposition temperatures on the microstructure and mechanical properties of Al 2024 cold sprayed coatings

Cold spray is a coating technology that works at temperatures below the melting point of the initial powder and appears to be an interesting alternative to repair aeronautical components. This work evaluates the effect of temperature on the quality and properties of the aluminum alloy 2024 coatings deposited by cold spray. The coatings were sprayed at a conventional temperature of 350 °C and at a non-conventional one of 500 °C on aluminum 2024 T351 substrates. Electron microscopy was used to analyze the microstructure. Depth sensing indentation and Vickers microhardness tests were conducted to determine the elastic modulus and hardness. Both coatings exhibited a work hardened microstructure, and no modifications in phase composition were observed. However, the coating processed at 500 °C presented hardness values lower than those obtained for the coating processed under conventional conditions. The hardness of the coatings increased regarding to the initial powder particles due to the plastic deformation induced during spraying. Comparing both coatings, the study indicates that cold spray at 500 °C could be adequate for maintaining and overhauling aluminum components used in the aeronautical industry.