The use of additively manufactured metallic materials for mechanical components submitted to fatigue loadings requires an advanced control of process parameters and resulting microstructures and defect. Indeed, the fatigue performance of such materials is closely linked to the inherited microstructure and the defects. As such, the effect of building direction on fatigue performance remains particularly challenging as it could produce a significant anisotropy of microstructure and defect populations. This work tries to contribute to a better understanding of the effect of printing direction on fatigue performance for three different material/process couples of steels: alloys AISI420, 316L and MA789 all produced by Powder Bed Fusion - Laser Beam (PBF-LB) process. High cycle fatigue performances are analyzed for machined specimens under fully reversed loading conditions. The analysis of damage mechanisms confirms the predominant role of defects on fatigue performance of materials elaborated by PBF-LB process. The effect of the defects on fatigue strength is quantitatively assessed through statistical analysis of critical defects populations and classical Kitagawa - Takahashi approach. It aims to assess the relative impact of defects on the fatigue strength in comparison to other factors like grain size and anisotropy originating from printing strategy.
|Poster Session||00:00-00:00||Driss El Khoukhi|
113 – Influence of defects and building direction on fatigue performance of three additively manufactured steels