An integrated hybrid wire-arc directed energy deposition, friction stir processing, and milling system for multi-track, multi-layer part manufacturing

• The proposed integrated system can perform wire-arc DED, FSP, and milling without changing the system or moving the workpiece to produce fully dense multi-track, multi-layer bulk samples. • The hybrid process is able to completely close the pores/microcracks generated by the DED process and modify the columnar grains to sub-micron equiaxed grains. • The grain refinement and elimination of pores/microcracks lead to significantly improved yield strength and hardness without compromising ductility. Wire-based Directed Energy Deposition (DED) is a widely-used manufacturing method due to its high productivity and large part fabrication capability. Meanwhile, Friction Stir Processing (FSP) is a solid-state joining process that can modify microstructure and weld lightweight alloys. Additionally, wire-based DED printed parts need machining process to achieve the desired dimensional accuracy. To take advantage of all these three processes, this work proposes an integrated hybrid system by combining the wire-arc DED, FSP, and milling processes into a standalone system which can fabricate superior materials in a multi-track, multi-layer manner for the first time. The integrated system can improve dimensional accuracy and productivity by processing the workpiece without the need to move it between different systems. It is demonstrated that a 150 × 40 × 21 mm 3 block of aluminum alloy AA5183 can be fabricated using the hybrid wire-DED/FSP/milling process from wire feedstock. Material characterization shows that the hybrid process is able to refine the grain size by two orders of magnitude to sub-micron scale, while eliminating all the pores and microcracks produced by the DED process. These enhancements result in significantly improved mechanical properties including Young's modulus (15%), yield strength (161%), ultimate strength (33%), and hardness (55%) without compromising ductility.