Cold spray deposition of heat-treated Inconel 718 powders

In the present work, Inconel 718 powder manufactured by gas atomization was successfully heat treated over the range of 600-900^oC to induce a microstructural modification. In the last years, the solid-state deposition technology cold spray has been explored as a repair technology for metallic components. However, cold spraying of high strength alloys such as Inconel 718 is still challenging due to the localized segregation of alloying elements that results in limited particle deformation, degrading the deposit quality and properties. Powder heat treatment to modify its deformation behavior during cold spraying has been recently developed for aluminum alloys, however, there is no literature reported for Inconel 718. As-atomized and as-heat treated powders were used for high pressure cold spray deposition. The macrostructure and microstructure of the resultant deposits were evaluated. Heat-treated powders showed the precipitation of carbides at 800^oC and precipitation of d phase at 900^oC. Deposits sprayed using heat-treated powders showed higher thickness per pass as well as higher powder particle deformation as compared with using as-atomized powder improving interparticle bonding and decreasing deposit porosity. These results contribute to increase the ability of cold spraying Inconel 718 by performing powder heat-treatment.