Enhancing the bond strength in the meta-crystal lattice of architected materials by harnessing the non-equilibrium solidification in metal additive manufacturing

Abstract Architected materials produced by metal additive manufacturing techniques offer realization of complex structural hierarchies that mimic the principles crystal plasticity while still being ultralight-weight. However, they suffer from deep-rooted multiscale defects including microstructural heterogeneity caused thermo-mechanical transients in melt pool. Here we manufacture meta-crystal 316L stainless steel microlattice structures for utilizing strain localization mechanism bulk akin to dislocation slip mediated plasticity. These lattices are characterized here using scanning and transmission electron microscopy, along with energy dispersive spectroscopy (EDS) backscatter diffraction (EBSD) reveal microstructural, chemical crystallographic orientation information at various locations struts joints. The presence inherent voids was major drawback would undermine their performance as mechanical metamaterials. Nevertheless, other form spatially correlated networks micro-segregated cellular substructures overcome strength-ductility trade-off render comparable engineering conventional steels. By exploiting this intrinsic strengthening due rapid (i.e. non-equilibrium) solidification phenomenon, bond strut) strength meta-crystals can be enhanced (or controlled) on top employing hardening metallurgy design architected tailored properties.