Mechanical Property Mapping of Cold Sprayed Ti Splats and Coatings

Profile nanoindentation and nanoindentation mapping were used to investigate the mechanical properties of commercially pure cold spray Ti splats and coatings deposited at increasing deposition velocities. Three regions in the cold spray Ti splats have been indentified: the impact region, the jetting region, and the upper splat region. The mechanical properties measured in these regions were tied to the cold spray deposition process with help of optical and scanning electron microscopes. The jetting region was observed to contribute to a metallurgical bonding of cold spray splats to cold spray splats and was measured to have low hardness in comparison to the splat impact site and similar to the hardness in the upper splat region. No increase in the profile coatings hardness with increase in the particle in-flight velocity and coating thickness was found. A correlation between the mechanical properties and the presently known deposition temperature, stress and dislocation density models was made.