Size-Dependent Microstructure of Electron Beam Melted Ti-6al Alloy

Abstract

The Powder Bed Fusion (PBF) techniques allow for the production of complex-shaped components, yet geometric variations lead to varying mechanical properties within the fabricated structures. Despite employing the same manufacturing process, specimens of different sizes exhibit distinct microstructures. This study compares the microstructures of Electron Beam Melted (EBM) Ti-6Al-4V samples with build diameters of 6, 7.5, and 15 mm by examining alpha (α) phase thickness, dislocation densities, and hardness. Lattice parameters of phases and dislocation densities in the specimens are compared through X-ray diffraction (XRD) analysis. Notably, the study finds that α phase thickness increases with an increase in build diameter. The results demonstrate that size-induced differences in microstructure led to variations in mechanical properties. This highlights the crucial need to consider size effects in the design and assessment of complex PBF-fabricated structures. © European Powder Metallurgy Association (EPMA)