Metamaterials, also known as lattice‐structured materials, imitate the multifunctionality of natural architects as tailoring their physical properties is associated with manipulating their microstructure. As the recent evolution of additive manufacturing enables the creation of intricate geometries with minimal material wastage, improving the design to manufacturing cycle of lattice structured materials has become one of the trending research areas. Triply periodic minimal surface (TPMS) and plate lattice materials are renowned for their exceptional mechanical behavior in lightweight applications. Apparently, several types of design optimization strategies are explored to maximize their performance for better biocompatibility and mechanical loading resistance. Some of these strategies include functional gradation and multimorphology hybridization that are comprehensively described in this review. Their benefits and drawbacks are highlighted with a focus on TPMS and plate lattice materials. The review anticipates the utilization of automated design exploration methods (i.e., topology optimization and data‐driven methods) to further enhance the design optimization procedure of lattice structured materials.

In this paper, thin layers of NiTi shape memory alloy (SMA) triply periodic minimal surface lattices (TPMS) are fabricated using laser powder bed fusion (LPBF), considering different laser scanning strategies and relative densities. The obtained architected samples are studied using experimental methods to characterize their microstructural features, including the formation of cracks and balling imperfections. It is observed that balling is not only affected by the parameters of the fabrication process but also by structural characteristics, including the effective densities of the fabricated samples. In particular, it is reported here that higher densities of the TPMS geometries considered are generally associated with increased dimensions of balling imperfections. Moreover, scanning strategies at 45° angle with respect to the principal axes of the samples resulted in increased balling.

In powder bed additive manufacturing processes, factors like moisture, oxidation, and surface contamination can impact powder cohesion leading to flow behavior degradation and ultimately part quality-related issues. Unfortunately, most of the existing powder characterization tools are either time-consuming/expensive to run or lack required sensitivity to precisely assess variations in powder surface conditions. Triboelectric charging, a phenomenon resulting from the contact and separation of materials, has recently gained attention as a method allowing differentiation of powder surface composition. Triboelectric charging is highly influenced by several powder characteristics including particle size, morphology, and surface composition. The focus of this presentation is to highlight the effect of surface chemistry on the triboelectric charging behavior of various aluminum alloy powders. This presentation will show the links between tribocharging response of various powders and their X-ray photoelectron spectroscopy (XPS) signature, to demonstrate how triboelectric charging can be used as a quick method to characterize powder surfaces.

In powder-based additive manufacturing (AM), thermal exposure during processing can modify powder surface chemistry and promote oxide growth, even under inert atmospheres from residual oxygen contamination. This study investigates the effect of thermal oxidation on the surface chemistry and triboelectric charging behavior of three AM metal alloy powders: AlSi10Mg, 316L stainless steel (SS 316L), and Ti6Al4V. The work examines the evolution of the oxide layer during baking at 100 and 300 °C using triboelectric charging corroborated by X-ray photoelectron spectroscopy (XPS), diffuse-reflectance spectroscopy, and work-function measurements. The results show that heating modifies the surface oxide state of all powders, with changes dependent on the alloy composition and baking temperature. For AlSi10Mg, heating modified the Al₂O₃-rich surface oxide, with changes consistent with increased oxide ordering and γ-Al₂O₃-like characteristics, with the work function increasing from 4.34 ± 0.01 eV in the as-received (AR) condition to 4.92 ± 0.03 eV after baking at 300 °C. The corresponding triboelectric $n$-exponent increased from 0.91 to 1.38. For SS 316L, transformation of Cr(OH)₃ to Cr₂O₃ reduced triboelectric charge accumulation, while the oxygen concentration increased from 49.92 to 54.87 at.% and the work function decreased from 5.74 ± 0.02 to 5.28 ± 0.04 eV after baking at 300 °C. This reflected a drop in the $n$-exponent from 0.82 for AR to 0.73 at 300 °C. For Ti6Al4V, charging variations were associated with titanium oxide evolution and surface modifications consistent with rutile-related titanium oxide characteristics, with the work function increasing from 5.33 ± 0.01 to 5.44 ± 0.03 eV after baking at 300 °C. The corresponding triboelectric $n$-exponent increased from 0.49 to 0.52. Overall, triboelectric charging is a sensitive approach for detecting thermally driven surface oxide modifications in additive manufacturing powders.