Basic Research of Directed Energy Deposition for Aluminum 4043 Alloys Using Pulsed Variable Polarity Gas Metal Arc Welding

Additive manufacturing of metals is actively being researched due to its potential for mold modification and cost savings. However, producing smooth aluminum parts with directed energy deposition (DED) using welding heat flux presents material restrictions and challenges. While research has focused on developing cold metal transfer (CMT) with minimal heat input, its application can be costly in industry. To address this issue, we checked over a DED process using pulsed variable polarity (VP) gas metal arc welding (GMAW), which, for the first time, reduces costs compared to CMT. Optimal parameters were determined via experimentation, with deposition efficiency (DE) used to evaluate post-processing loss and deposition performance. Tensile tests were conducted to verify the mechanical properties of deposited specimens, and microstructure analysis was performed. In this study, method achieved a stable deposition tendency with an electrode negative ratio of 18% under the welding conditions of an ER4043 Ø1.2 electrode wire, 120 A, 21 V, 80 cm/min, a shield gas flow rate of 20 L/min, and bead-on-plate position. By varying the layer-by-layer velocity throughout the deposition process, a maximum DE of 82.56% was achieved, resulting in lower post-processing loss than CMT with suppressed anisotropy in the material. Tensile test data and microstructure inspections confirmed isotropic behavior. For the first time in the field of study, this research proved that deposition process by VP-GMAW is cost-effective compared to CMT.