The Influence of mesostructure on the microstructure and mechanical properties of Selective Laser Melted Ti-6Al-4V alloy lattices

Selective Laser Melting (SLM), an Additive Manufacturing (AM) process, has been used to manufacture Ti-6Al-4V lattice structures to investigate the influence of mesostructure on the microstructure and the mechanical properties. Different lattice structures with different features such as thin sections, curvature, and build angle were examined. The study results revealed that, while much of the material consists of columnar grains with similar alignment, there is an area near to the inner surface with anisotropic orientation. These results led to a further investigation into the connection between the lattice crystallography and the mechanical properties by designing lattice structures capturing this phenomenon. This study confirmed that the build orientation and post treatment have an effect on the elastic behaviour of the structure, though in the example tested here, the strength is not affected to a significant extent. Numerical modelling was used to assess the impact of microstructural inhomogeneity on mechanical properties, and this goal has been achieved by changing the material orientations, which led to changes in the lattice stiffness.