Additive Manufacturing of Anisotropic TC4 Cubic Hollow-Strut Lattice Structures with High Specific Yield Strength: Optimization, Properties, and Failure Modes

Additive manufacturing permits the precision design and meticulous fabrication of lattice structures, thereby unlocking their potential performance capabilities. Herein, to enhance the specific strength of the cubic lattice structure, three design strategies are applied: substituting solid struts with hollow ones, increasing the material proportion of vertical struts, and introducing cross plates into the hollow struts. The results demonstrate that the strategy of substituting solid struts with hollow ones effectively contributes to a substantial enhancement of 113% in the compressive yield strength of lattice structures. Furthermore, increasing the vertical material proportion from 70% to 85% while maintaining a constant relative density of 0.30, a significant enhancement is observed in both yield and ultimate strength. Additionally, introducing cross plates into the hollow struts at a vertical material proportion of 90% results in a remarkable enhancement of the specific yield strength to 230 MPa cm3 g-1, significantly surpassing that of the TC4 matrix. The optimized lattice structures exhibit exceptional uniaxial strength, tremendously exceeding the predicted limits of the Gibson-Ashby model. Thus, the Gibson-Ashby model is modified by considering the vertical material proportion Cv. These findings are expected to establish a foundational framework for the optimizing of anisotropic lattice structures by remarkably enhancing their specific strength. To enhance the specific strength of cubic lattice structure, three design strategies are applied: substituting solid struts with hollow ones, increasing the material proportion of vertical struts, and introducing cross plates into the hollow struts. The specific yield compressive strength of the optimized lattice structure reaches up to 230 MPa cm3 g-1, significantly surpassing that of the TC4 matrix.image (c) 2024 WILEY-VCH GmbH