Deformation behavior of metallic lattice structures with symmetrical gradients of porosity manufactured by metal additive manufacturing

Abstract

Additive manufacturing of complex metallic parts is a topic of broad interest among researchers as it is imperative for critical applications like aerospace parts and biomedical implants. In this work, Functionally Gradient Lattice (FGL) structures confined within top and bottom solid skins are designed and additively manufactured (AM) by Selective Laser Melting (SLM) using Ti–6Al–4V powder. The SLM fabricated samples show the presence of a martensitic microstructure with the strut dimensions correlating with the CAD struct dimensions with slight variations in the micron regime. The struts were attached with non-melted Ti6Al4V powder particles, characteristic of the SLM process. The manufacturability and compressive performance of the struts were assessed, and the deformation behavior was studied using Digital Image Correlation (DIC) technique. The usability of the FGL structures is elucidated by comparing their uniaxial compression test results with uniform BCC structures of the same relative density (RD). The gradient structures were found to function better in both energy absorption characteristics and strength.