Eliminating Graphite in Additive Friction Stir Deposition

Additive Friction Stir Deposition, also know as MELD, is a solid-state, near-net-shape metal additive manufacturing process. As a solid-state deposition process it relies on deformation of metals below the melting point, which leads to significant benefits in microstructure and properties of the printed material. While the properties and deposition rates of additive friction stir deposition lead metal additive processes, initial work has been developed using graphite lubricants on the metal during the deposition process. These lubricants can at times find themselves within the overall deposition of the metal in such a way as to significantly reduce the as-deposited properties of the build. We show a comparison of properties of 7xxx serious aluminum with on without graphite contamination, as a means of justifying the need for eliminating the use of graphite in additive friction stir deposition. Furthermore, we show a design for eliminating graphite and evaluate the proposed design on two separate manufacturers platforms for additive friction stir deposition.