Geometric deviation and compressive failure of Ti-6Al-4V alloy honeycomb structures printed by laser powder bed fusion examined by X-ray microcomputed tomography

Abstract While 3D metal printing is extensively employed for fabricating honeycomb structures, the evaluation of their printing quality and defects remains challenging due to technical limitations. This work aims to investigate the influence of printing defects, honeycomb geometries, and printing orientations on the compressive mechanical properties of laser powder bed fusion (L–PBF) Ti-6Al-4V cylinders. Honeycomb cylindrical samples were fabricated with the size of Ø5 mm × 10 mm. X-ray microcomputed tomography (micro-CT) was employed to study geometric formation accuracy and printing defects. The printed honeycomb cylinders were then subject to compression testing, and fractured cylinders were rescanned by micro-CT to study the compression-induced failure behaviors. The findings demonstrated that printed Ti-6Al-4V honeycomb cylinders exhibited varying build quality, porosity, dimensional inconsistency, and partially melted or unmelted powder particles. The vertically printed honeycomb cylinder exhibited higher geometry accuracy than the horizontally printed honeycomb cylinder. The designed honeycomb structures and printing orientations had a significant influence on the nominal modulus. Both the vertical and horizontal printing honeycomb cylinders exhibited compression-induced shear failure. This work describes a micro-CT examination technique for investigating the structural integrity and mechanical failures of 3D metal-printed honeycomb structures.