Enhanced surface finish and reduced porosity of TiC nanoparticles reinforced 2219 aluminum alloy deposit fabricated via oscillating laser-arc hybrid additive manufacturing

Additive manufacturing (AM) of ceramic particle reinforced aluminum alloy has drawn increasing attention due to the refined microstructure and improved mechanical properties in as-deposited condition. However, it is still challenging to make defect-free ceramic particle reinforced aluminum alloy deposit with desirable surface finish using wire-based AM technique because of the special thermophysical properties of the incorporated ceramic particles. In this work, a novel oscillating laser-arc hybrid additive manufacturing (OLHAM) technique was developed to fabricate TiC nanoparticles reinforced 2219 aluminum alloy deposit. The surface finish and porosity were evaluated using optical microscope and 3D XCT, respectively. Compared with wire-arc additively manufactured (WAAMed) deposit, the surface roughness and volume porosity of OLHAMed deposit decreased by 46.0 % and 88.3 %, respectively. In-situ high-speed photography was used to observe the arc and molten pool behaviors to understand the mechanism of enhanced surface finish and reduced porosity. The enhanced surface finish was attributed to smaller layer width fluctuation and higher arc stability, which resulted from the action of the hybrid heat source. The elimination of large droplet transfer, which caused pores in the WAAMed deposit, and the promotion of molten pool fluidity resulted in much lower porosity of the OLHAMed deposit.