Cold spraying of aluminum alloys – Connection between particle in-flight velocities and microstructural details for process optimization

Cold spraying has many advantages in repair and restoration applications. High performance and repairability are of great interest in different sectors e.g., in aviation and manufacturing industries. For these purposes, high quality of the repair and reproducibility in repaired material properties are important features. Cold spraying makes it possible to produce coatings and repaired materials from several materials. In order to optimize the cold spray processing, process control is advantageous for achieving the best combination of process parameters and coating properties. In this study, we focus on cold spraying of aluminum alloy feedstock and the properties of these coatings on the similar substrate material. The process optimization is done using online particle velocity and density measurements by S-PTV (sizing-particle tracking velocimetry) from the spray jet and by carrying out a detailed microstructural analysis using electron microscopy and EBSD (Electron Backscatter Diffraction) analysis for the selected coatings. Dense, highly deformed and high-quality aluminum alloy coatings can be prepared using high-end spray parameters. This indicates potentiality of repairing similar materials by using cold-sprayed aluminum alloy coatings.