Charakterisierung der Oberflächentopographie von Laser Powder Bed Fusion erzeugten IN718-Proben
Aachen (2020) [Dissertation / PhD Thesis]
Page(s): 1 Online-Ressource (VI, 181 Seiten) : Illustrationen, Diagramme
In this thesis, the surface topography of samples made from the material Inconel 718(IN718) and produced with the additive manufacturing process Laser Powder Bed Fusion (LBPF) is investigated. Because of the layer wise additive build in the powder bed, the surface topography can be described by the characteristics layer structure, powder adhesion and weld pool extension. The resulting consequences of these characteristics are reduced dynamic material properties and restrictions for the non-destructive component inspections for defects and imperfections. These consequences are the motivational basis for this thesis and the starting point for the characterisation of the surface topography of samples made from the material IN718. Initially the characteristics of the surface topography is described and production specific characteristics are highlighted for further considerations. Different sample geometries are produced with various manufacturing parameters (vertical, upskin and downskin). The surface topography of these samples is characterised with different profile and surface area roughness values and the material of the border zones are analysed with metallographic investigations. The characteristic values and features found suitable through measurements and analysations are also applied on LBPF surfaces which are treated with an abrasive blasting process or mechanical grinding. The abrasively blasted surfaces serve as reference surfaces to specify target values for the surface topography of untreated LBPF samples directly after the additive manufacturing process. The developed characteristic values and features are summarised in an evaluation matrix for LBPF and treated surfaces. By using design of experiment samples are produced in a modified process which surfaces and border zones are characterised with the characteristic values and features and compared with the reference surface and the surfaces from the non-modified process. In conclusion the comparison shows that by using the modified process similar characteristic values and features to the reference surface can be achieved.
Schmitt, Robert Heinrich