A Review on Twin Wire Arc Additive Manufacturing of Metals and Alloys: Microstructure and Mechanical Properties

Abstract

Wire Arc Additive Manufacturing (WAAM) has been considered one of the promising Additive Manufacturing (AM) techniques for fabricating medium to large-sized metallic components, even with complex geometry. WAAM offers numerous advantages, such as high deposition rate, lower material utilization, and non-hazardous properties compared to powder-based processes. With the use of multiple feed wires, WAAM achieves an advantage of in-situ alloying. This technique allows the use of various multiple feed wires to form complex components with good mechanical properties. The use of multiple feed wires fixes the problem of limited availability of some metal wires that are difficult to form due to particular metal properties like brittleness and increases the deposition rate. In recent years, Twin Wire Arc Additive Manufacturing (T-WAAM) has become popular for fabricating functionally graded materials (FGMs), intermetallic alloys, and other multi-element alloys. This article reviews the various studies related to the T-WAAM technique for fabricating structures of different alloys. Besides, microstructure studies and mechanical properties of the fabricated structures along with the process feasibility are discussed. In-situ alloying offers a cost-effective method for producing various alloys and composites with desired compositions and directional properties. However, it would be appealing to develop a WAAM system combined with other secondary machining processes to fabricate finished components with minimal or no need for post-processing. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.