The State-of-the-Art on Properties Enhancement by Post-heat Treatment of WAAM Fabricated Alloys

Over the past few years, wire arc additive manufacturing (WAAM) has become one of the promising additive manufacturing technologies for fabricating cost-effective medium to large-scale near-net shape metallic components with desirable mechanical and metallurgical performances. Researchers are inclining more toward the process due to its higher deposition rate, material utilization and efficiency while using the same conventional welding setup. Nowadays, WAAM has been involved with a wide range of metals and alloys such as aluminum (Al), nickel (Ni), titanium (Ti), magnesium (Mg), steel (Fe), and their alloys, and even functionally graded material (FGM) also. The most common defect associated with the wire arc additive manufacturing (WAAM) process is anisotropic behavior due to the formation of a highly textured structure or crystallographic orientation caused by directional grain growth. Other typical defects are residual stress, porosity, cracking, and delamination. These defects affect the mechanical behavior of the metallic parts tremendously. To build a sound product by minimizing the effect of these defects, researchers have gone through a few post processing approaches, especially heat treatment on the wire arc additive manufacturing (WAAM) printed components. It is reported that heat treatment is the most effective approach to modifying the microstructure of WAAMed fabricated ferrous or non-ferrous parts. It can control residual stresses, deformation, hardness, ductility, and other mechanical properties. This review article summarizes the defects in WAAMed deposited components and the effect of post-heat treatment on those components’ metallographic and mechanical characteristics.