Depositing Titanium Alloy Additive Features to Forgings and Extrusions Usingthe Cold Spray Process

摘要

Development of new low-cost methods for spray formingTitanium alloys is critical for many industries. Directfabrication technologies would have an impact on manyindustries because of the potential for quick manufacture ofparts or additive features with minimal waste. For example,in the aerospace industry the buy to fly ratios can vary from1.5:1 for turbine blades to over 22:1 for structuralmembers. The buy to fly ratio is the mass of material that isrequire to machine a part compared to the mass of material inthe finished part. For compressor and ring sections, the ratiois approximately 12:1. For this family of parts, an analysis byPratt & Whitney [1] indicated that the buy to fly ratio could bereduced by 41% to 7:1 if cold spray could be implemented todeposit isogrids, structural ribbing, bosses, and flangesreducing the material, machining, and post processingrequired for the final part. This paper summarizes the resultsof experiments conducted in Phase I of a National ScienceFoundation grant to spray form Titanium alloy using the coldspray process. This paper further describes the studiesperformed to date in Phase II and the techniques used todecrease the porosity of the as-sprayed coating from 18% tobetween 2% and 5% and the post processing methodsemployed to further consolidate the coating and restore the assprayedmaterial to near wrought properties.