Mechanical and corrosion behavior of sheet-based 316L TPMS structures

Abstract

Sheet-based triply periodic minimal surface (TPMS) lattices with different unit cell types (diamond, gyroid, fischer, IWP, and primitive) were fabricated from 316L stainless steel using laser powder bed fusion. Scanning electron microscope was used to evaluate the dimensional accuracy and the printing defects in different architectures. The tensile and compressive deformation behaviors of TPMS structures were analyzed. The elastic modulus, the yield strength, and the energy absorption values show similar topology dependence under both compressive and tensile loading. The fischer structure showed superior mechanical performance under compression and tension than the previously reported sheet-based diamond TPMS lattice. The tensile properties of fischer structure for any metallic material are reported for the first time. The majority of sheet-based TPMS structures show high stiffness and plateau stress values indicating stretching dominated deformation. However, the primitive structure displayed the lowest resistance to deformation, likely due to a significant bending contribution. Electrochemical analysis was performed to study the corrosion of steel lattices in 3.5 wt.% NaCl. All lattice structures showed improvement in corrosion resistance compared to the solid sample. The mechanical and electrochemical properties will enable better understanding and selection of metal TPMS lattices for potential applications.