Laser Powder Bed Fusion Inconel 718 Lattice Structures: From Process Simulation to Microstructural and Mechanical Characterizations

Abstract Lattice are porous structures obtained by a controlled repetition in the space of a designed unit cell, resulting in reduced weight and unique functional characteristics such as high specific strength and stiffness, mechanical energy absorption, and heat transfer control. This work aims to tailor geometrical variables and process parameters to fabricate L-PBF Inconel 718 beam-based lattice structures, focusing on their novel use as support structures during the printing process of metallic components, enhancing structural integrity and heat dissipation. 3D models of different porous structures (cell type: FCC-Z) were developed varying geometrical parameters. Finite Element Method simulations were conducted by Ansys, validating its ability to meet quality standards for directional deformations and residual stresses. The simulation’s correlation with the coordinate measuring machine (CMM) analysis confirmed the accuracy of the model. Scanning electron microscopy (SEM) characterization was employed to analyze the deformation and failure characteristics of the lattices, excluding those with geometric parameters unsuitable for optimal support performance. Microstructural analysis revealed partial recrystallization in the heat-treated samples. The remaining dendritic structures indicate incomplete homogenization, particularly near the lattice. Precipitated strengthening phases such as γ′ and δ were identified, alongside minor quantities of η phases and MC carbides, which could influence ductility and strength. Vickers microhardness tests showed higher hardness in the heat-treated samples, particularly at nodes and struts, with a more uniform hardness distribution in heat-treated samples due to the precipitation of strengthening phases. This highlights the role of heat treatment in enhancing the material’s mechanical properties. Graphical Abstract