Mechanical Properties Evaluation Based on the Variable Gradient of Body-Centered-Cubic-Based Lattice Structure Prepared by Laser Powder Bed Fusion

The demand for structures and devices that can adapt, have multiple functionalities and specialized performance is increasingly growing, with functional gradient lattice structures receiving widespread attention in both the industrial and academic sectors. In this study, Ti-6Al-4V was used as the forming material, and laser powder bed fusion technology was employed to design six different density gradient variations based on the BCC lattice structure using exponential functions, both parallel and perpendicular to the loading direction. The results showed that the lattice structures with different density gradients parallel to the loading direction exhibited layer-wise collapse, with an increase in elastic modulus and plateau stress corresponding to an increase in the density gradient exponential function. Conversely, lattice structures with different density gradients perpendicular to the loading direction experienced diagonal shear failure, resulting in complete structural failure. Additionally, the fracture mode of the struts varied with their diameter size, and the fracture pattern of the lattice structures was a combination of brittle and ductile deformation. This study synthesizes the compression properties of various lattice structures using compression tests, proving that gradients with targeted strategies can be made to enhance structural performance and serve as a guide for designing density gradients for engineered lattices.