The challenges in edge detection and porosity analysis for dissimilar materials additive manufactured components

AM is being recognized as a core technology for producing complex and customized components. Several AM machines can manufacture components using dissimilar materials which provides a substantial advantage by combining the mechanical properties of several materials in a single component. However, there are several challenges stopping the industry from widely utilizing AM in critical components. The mechanical properties of AM components are not well understood, furthermore nondestructive testing (NDT) and repeatability are not well established. X-ray computed tomography (XCT) is one of the most promising NDT methods that can detect porosity/defects and provide information regarding the position, location distribution and volume of any pores/defects. This paper presents a case study that highlights the challenges in edge detection and porosity analysis for AM manufactured components using dissimilar metallic materials. The artefact used in this experiment consists of two individual components built using Aluminium and Titanium powders that are then assembled together. The two components contain machined defect filled with unfused Titanium powder which prior to assembly were characterised using a focus variation microscope (Alicona G4) in order to determine the reference values for the diameter and depth of each defect. A Nikon XTH225 (Nikon Metrology, Tring) industrial XCT was used to analyse the pores/ defects’ location and size. The XCT data was reconstructed and the analysis for surface determination and defect analysis was carried out using VG Studio Max 3.1 (Volume Graphics, Heidelberg). The emphasis of the study is providing guidelines for selecting the inspection parameters, optimizing the surface determination to allow for porosity analysis and edge detection in dissimilar materials components built using in AM powder bed fusion (PBF).