Development of a novel twin-wire arc additive manufacturing system for in situ alloying

Abstract

Over the past decade, the utilization of additive manufacturing has gained momentum due to its near-net manufacturing capabilities, design adaptability, and expedited production capabilities. Wire-based additive manufacturing techniques offer promising avenues for the fabrication of metal parts with high deposition rates, low costs of materials and equipment, and strong structural integrity. However, existing wire-based, mostly gas tungsten arc welding (GTAW), and plasma-based techniques face many challenges due to process design complexities, expertise requirements, and higher costs. A twin-wire arc additive manufacturing (T-WAAM) system was developed using two gas metal arc welding (GMAW) systems because it was easier to weld, cheaper, and had higher deposition rates than the other wire-based techniques. Two GMAW systems were physically integrated, and torches were aligned 60° to each other for the wires to meet, melt, and form an alloy. The setup was calibrated with different parameters and was found to have a maximum error of 1% in distance, a decrease in time deviation with an increase in speed, and a decrease in percentage time deviation with distance. The process parameters were then optimized using the Box–Behnken and analysis of variance (ANOVA) techniques using two different wires of nickel and titanium. Using the optimal parameters, a sample was deposited and characterized for its microstructure, phases, phase transformation temperatures, and mechanical properties. The results displayed an excellent mixture with higher mechanical properties, confirming that the developed T-WAAM setup can be a competitive option compared to existing wire-based directed energy deposition techniques for developing alloys.