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Christopher Lefky1 Abdalla Nassar4 Timothy Simpson2 3 Owen Hildreth1

1, Arizona State University, Tempe, Arizona, United States
4, The Pennsylvania State University, State College, Pennsylvania, United States
2, The Pennsylvania State University, State College, Pennsylvania, United States
3, The Pennsylvania State University, State College, Pennsylvania, United States

Additive manufacturing typically necessitates the inclusion of support structures to provide a thermal pathway for heat dissipation and provide a base for overhanging surfaces. Directed energy deposition (DED) is a common method to 3D print metals, chosen since multiple materials can be printed serially. Dissolvable supports are a common method for removing these sacrificial structures in the printing of plastics due to the low effort and time associated with the process. The presented work adapts this process for DED printed structures and models the entire part as a functionally gradient material (FGM). FGM materials are chosen to provide varying properties across the gradient. By printing a gradient transitioning from an austenitic stainless steel build substrate to low chromium steel to stainless steel we successfully lower the corrosion resistance across the gradient.
This presentation will detail an investigation into the resultant properties across the gradient such as microstructure, chromium concentration, and etch rate. Additionally, we will show that incomplete mixing is prevalent within tracks, necessitating the consideration of properties across the gradient, as appose to just the outer layer. These variations across both layers, tracks, and within a single track are important to consider when developing a process for DED printed dissolvable supports.

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