Mechanical behaviour of Ti6Al4V lattice structures manufactured by Electron Beam Melting

Additive manufacturing (AM) technologies allow the design and production of complex geometries, including structures designed to exhibit superior mechanical performance. Among these designs, there is growing interest in utilizing metal lattice structures, with specifically required properties, minimizing weight, for applications in both the mechanical and medical fields. The mechanical properties of such structures are strongly influenced by their shape and size.This study aims to investigate the influence of lattice topology, cell dimensions and beam diameter on the deformation and failure mechanisms of Ti6Al4V alloy structures manufactured by EBM under static compressive loading. A Design of Experiment (DOE) methodology was employed to determine the geometric parameters and dimensional characteristics of the unit cell for the final specimen configuration. A total of fifteen topological combinations was obtained and forty-five lattice specimens with three replicas for each cell type were manufactured with random order process to minimize manufacturing time variation and dependence. The full experimental testing results were analysed and compared in absolute terms and related to lattice density. Furthermore, a deep experimental microscopic analysis was conducted for a statistical analysis of representative beam diameters and real cell sizes for lattice samples. Additionally, micro-computed tomography (micro-CT) inspection was employed to verify defect presence (such as porosity) that may affect the mechanical behaviour.