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Lattice structures of 100Cr6 steel were manufactured from metallic-based inks by robotic-assisted deposition (robocasting) using Pluronic F-127 solution. The stability and pseudo-plastic behavior of the ink were optimized, and allowed printing through 200–840 μm nozzles, leading to macroporous architectures composed of 300–600 μm diameter rods separated by 90–350 μm pores, after debinding and sintering. A second level of porosity (sub-micron size) was controlled by adjusting the sintering temperature. The linear shrinkage due to drying and thermal consolidation was evaluated from images obtained by micro-tomography and volumes measured by mercury intrusion porosimetry. Whatever the thermal treatments, the microstructure was always mainly composed of ferrite – α. The mechanical properties were estimated both at a local level (Young modulus and hardness of the rods by nanoindentation, coherent with those of 100Cr6 steel) and at the architecture level (stress-strain curve of the structures, showing a plastic behavior related to a good consolidation of the structure). Thus, dense metallic lattice structures with a regular macroporosity and interesting mechanical properties can be easily obtained with these water-based metallic inks, which do not require a complex formulation nor high organic content as reported in literature. Keywords: Additive manufacturing, Robocasting, Mercury intrusion porosimetry, X-ray micro-tomography, Microstructural characterization, Mechanical properties

The microstructure of grade X4CrNiMo16.5.1 stainless steel was studied at different scales. The chemical composition of the native passive film formed on the different phases was then determined at the microscale. The degree of homogeneity of the native passive film is discussed. Subsequently, the susceptibility to pitting corrosion of X4CrNiMo16.5.1 was quantified using the electrochemical microcell technique. The nature of precursor sites and the morphology of pits were investigated by combining scanning electron microscopy with Electron BackScatter Diffraction and potentiostatic pulse tests. The role of the microstructure and the cold-worked layer generated by polishing in pitting is discussed.