Development of the microstructure and mechanical properties of cold-sprayed IN718 alloy coating by a novel in-situ shot peening process

Mechanical properties of cold-sprayed Ni-based alloy coatings depend remarkably on their microstructures, especially the porosity. In this study, in-situ shot-peening approach was introduced by mixing large stainless steel (SS) shots diameters over 150mm with IN718 spray powders to aim at developing a novel approach to achieve dense coating. The effect of mixed stainless steel short content on the microstructure and mechanical properties of the IN718 coating was examined. Results show that IN718 coating can be deposited without any shot peening particle inclusions for their relatively low velocity due to large size. It will be revealed that the deposition efficiency of the IN 718 powders is improved by the in-situ shot peening effect. With increasing shot peening fraction in the powder mixture from 0% to 50 vol.%, the porosity was decreased from 5.6% to 0.2%. Remarkable work hardening induced by impact of the shot peening particles was detected.