Study on the microstructural and hardness variations of unsupported overhangs fabricated using selective laser melting

Inconel 718 (IN718), a nickel-based superalloy, is commonly used in rocket nozzles and turbines. Conventional manufacturing of complex IN718 geometries is difficult due to its high stiffness values. Consequently, Additive Manufacturing (AM) methods like selective laser melting (SLM), offers a viable solution for the fabrication of parts using IN718 with high accuracy. One of the limitations of this technique is its need for supports in order to fabricate overhanging structures. These supports need to be designed carefully and tend to consume a significant amount of resources. In this research, we studied the angled structures fabricated without supports. The overhangs were fabricated using uniform process parameters for varying thicknesses. Microstructural and hardness analyses were carried out to determine variations in melt pools and Vickers hardness. The outcome of this study will help us in predicting the need for supports in overhangs and inclined structures used within a part having complex geometry.