Assessment of microstructure development, defect formation, innovations, and challenges in wire arc based metal additive manufacturing

The demand for additive manufacturing of large-size metallic components at optimum cost with high deposition rates (ranging from 1 to 10 kg/hr.) has driven substantial progress in understanding the wire arc additive manufactured (WAAM) products in terms of metallurgical and mechanical properties of the produced parts. WAAM technology has progressed and expanded to include various materials and applications. The aerospace and automotive industries use the WAAM technique to manufacture complex product structures. This article comprehensively analyzes recent research on the WAAM process and the metallic materials used. It offers an in-depth overview of the microstructural and material properties of WAAM-deposited parts, highlighting common defects found in WAAM components across various alloys, including porosity, deformation, and solidification cracking. The paper concludes that while WAAM holds great potential, its widespread application still faces numerous challenges that must be addressed in tailored ways for different materials to achieve a functional system within a reasonable time frame. Additionally, it explores methods to enhance the quality of WAAMed components by considering the specific requirements of various alloys. The study also explores innovative methodologies like simulation, modeling, and the incorporation of artificial intelligence to optimize the overall performance of WAAM. Furthermore, it provides an in-depth analysis of various techniques aimed at enhancing the quality of WAAM components, including near-immersion active cooling, interpass cooling, hot forging, and interpass rolling.