Micromechanische Karakterisatie van warmtebehandeld Ti-6AI-4V vervaardigd via Laser Poeder Bed Fusie (L-PBF)

Ti-6Al-4V components with complex geometries are increasingly utilized in the aerospace, automotive, and biomedical industries due to their high strength-to-weight ratio and design flexibility. Laser Powder Bed Fusion (L-PBF) is a promising manufacturing method for producing these parts, offering intricate design capabilities, minimal material waste, and on-site production. However, the rapid cooling inherent to L-PBF introduces high tensile residual stresses and leads to the formation of martensite (α′), which reduces ductility. Therefore, post-heat treatment is essential to relax residual stresses and decompose the α′ phase into a mixture of α and β phases. Despite ongoing research, several key aspects—such as phase transformations during heat treatment and the deformation mechanisms of heat-treated components—remain poorly understood. This thesis aims to address these gaps by employing various in-situ monitoring techniques. First, the phase transformations and residual stress relaxation during heat treatment were investigated using in-situ high-energy X-ray diffraction (HEXRD) and dilatometry. Second, the deformation mechanisms of the heat-treated components were studied through in-situ uniaxial tensile test with HEXRD. Third, an in-situ tensile test was conducted inside a scanning electron microscope (SEM), utilizing digital image correlation (DIC) for strain mapping to link the strain localization and damage nucleation in a heat-treated component.