Deformation and Fracture Behaviors of Heterostructured STS316L/Inconel 718 by Laser Powder Bed Fusion

The current study utilized a two-step laser power bed fusion ( LPBF) method to create a heterostructured material (HSM) composed of STS316L and Inconel 718. STS316L enhances ductility, while Inconel 718 improves strength. We examined the tensile deformation behavior of HSMs and found that stress is mainly localized in the cell or grain boundary area. The volumetric ratio of Inconel 718 to STS316L in the HSM affects the tensile properties, although the structural design is crucial for improving tensile strength. Fractographic analysis revealed that fracture occurred and propagated at the STS316L and Inconel 718 interface, with evident unmelted powders due to insufficient energy density. Achieving an optimized process parameter is necessary to ensure a reliable chemical joining which increases the mechanical properties of HSM.