3D characterization of defects in deep-powder-bed manufactured Ti–6Al–4V and their influence on tensile properties

Deep-powder-bed additive manufacturing (AM) can lead to distinctive microstructural features. In this study, 300-mm long cylindrical rods (12-mm diameter) of Ti–6Al–4V were vertically built to the limit height of a commercial selective electron beam melting (SEBM) system for quantitative three-dimensional (3D) characterization of the defects by X-ray micro-computed tomography (μ-CT). Detailed μ-CT data from 18,337 consecutive slices revealed a strong dependence of defect characteristics on build height, including defect volume, population, sphericity, major axis length, depth and orientation angle. The first 100-mm build exhibited the worst presence of defects by each measurement, while the middle and last 100-mm builds contained much fewer defects, especially the last 100-mm build, which was free of lack-of-fusion defects (sphericity