Abstract

The development of contaminant-free additive friction stir deposition (AFSD) using 7xxx series aluminum alloys represents a significant advancement in solid-state additive manufacturing. The removal of graphite and other contaminants allows AFSD to more effectively move forward into the production space. This work demonstrates how contaminant-free depositions were made more feasible. This was accomplished via novel tool designs. These novel designs reduced process forces sufficiently that 7xxx aluminum alloys were able to be printed on commercial and research AFSD machines. Internal features such as draft angles and diffusers/chamfers help to significantly reduce actuator forces. This work also demonstrates how external tool features (knubs, scroll, and knub-scrolls) affected the layer interface when compared to a tool with no external features (flat). How the layer height affected the layer interface was also considered. It was found that the knub tool geometry presented with a more consolidated layer interface. The knub tool also ran lower process forces compared to other tools. These findings demonstrate the feasibility and advantages of graphite-free AFSD, offering a more efficient path toward structural component fabrication using 7xxx aluminum alloys.

Degree

College and Department

Ira A. Fulton College of Engineering; Manufacturing Engineering

Rights

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