On the role of interface strategy in multi-scale hybrid additive manufacturing.

As multiple macro scale directed energy deposition (DED) processes begin to be industrially adopted for large scale component manufacture, it is imperative that interface strategies between the processes are fully understood. The present work investigates the asynchronous deposition of a wire component (DED-arc), followed by a powder-based deposition (DED-LP) with varying surface treatments which were evaluated for flatness, porosity, hardness, and Charpy impact energy. The self-regulation effect of DED-LP was fully realized with up to 55% reduction in surface variation relative to the DED-arc surface. Contrarily, as surface contaminants were not removed between each process, the resultant DED-LP porosity was significantly reduced from 99.5% to 92.4%. Albeit the reduction in density did not negatively impact the impact toughness as evidenced by a low correlation coefficient of -0.46. As such, the overall manufacturing costs and application space must be considered for selection of the different interface strategies presented in the current work.