Únavové chování a modelování 3D titěného IN718: Vliv povrchových úprav a technik měření povrchu

V této studii byl zkoumán vliv různých povrchových úprav jako je pískování, vlečné omílání, soustružení, broušení a kombinace broušení + vlečné omílání, na drsnost povrchu a únavové vlastnosti 3D tištěného materiálu Inconel 718 . Hodnoty drsnosti získané ze dvou technik měření povrchu, tj. optické mikroskopie a rentgenové počítačové tomografie, byly porovnány. Obě techniky měření povrchu konzistentně naznačovaly, že všechny povrchové úpravy vedly ke zlepšení drsnosti, i když optická mikroskopie byla ovlivněna povrchovými odlesky a nadhodnocovala hodnoty drsnosti u omletého povrchu. V souladu s tím, všechny povrchové úpravy také vedly ke zlepšení odolnosti proti únavě, přičemž pískování a vlečné omílání přinesly nejmenší přínos, zatímco broušení + vlečné omílání vyšlo nejlépe.In this study, the effect of various surface treatments, including sand-blasting, drag-finishing, turning, grinding, and grinding + drag-finishing, on surface roughness (SR) and fatigue properties of laser beam powder bed fused Inconel 718 was examined. SR values obtained from two surface measurement techniques, i.e., optical microscopy and X-ray computed tomography, were compared. Both surface measurement techniques consistently indicated that all surface treatments led to improvements in SR, although optical microscopy was influenced by surface glares and overestimated the SR values of drag-finished surface. Accordingly, all surface treatments also led to improvement in fatigue resistance with sand-blasting and drag-finishing yielding the least while grinding + drag-finishing causing the most. Notably, only the cracks of ground + drag-finished specimens initiated from crystallographic facets while those in other conditions were surface initiated. Furthermore, by treating the surface valleys as micro notches, a modified fatigue notch factor model using a hybrid SR metric that incorporate several standard SR parameters was shown to correlate the fatigue lives of 94% of specimens with various surface conditions within a scatter band of three.In this study, the effect of various surface treatments, including sand-blasting, drag-finishing, turning, grinding, and grinding + drag-finishing, on surface roughness (SR) and fatigue properties of laser beam powder bed fused Inconel 718 was examined. SR values obtained from two surface measurement techniques, i.e., optical microscopy and X-ray computed tomography, were compared. Both surface measurement techniques consistently indicated that all surface treatments led to improvements in SR, although optical microscopy was influenced by surface glares and overestimated the SR values of drag-finished surface. Accordingly, all surface treatments also led to improvement in fatigue resistance with sand-blasting and drag-finishing yielding the least while grinding + drag-finishing causing the most. Notably, only the cracks of ground + drag-finished specimens initiated from crystallographic facets while those in other conditions were surface initiated. Furthermore, by treating the surface valleys as micro notches, a modified fatigue notch factor model using a hybrid SR metric that incorporate several standard SR parameters was shown to correlate the fatigue lives of 94% of specimens with various surface conditions within a scatter band of three