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6521 |
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Effect of substrate pretreatment on the fatigue performance of WC-Co coated additive manufactured 316L |
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Leif Gereon Hagen* / University of Dortmund, Germany Wolfgang Tillmann / Institute of Materials Engineering, Germany Kai-Uwe Garthe/ Chair of Materials Science, Germany Mirko Schaper/ Chair of Materials Science, Germany Kay-Peter Hoyer/ Chair of Materials Science, Germany |
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Several studies already identified that the fatigue strength of 316L parts processed by laser beam melting (LBM) is distinctly affected by the surface integrity. Among others, surface defects as well as residual stresses are of crucial importance. Despite new findings in the field of surface engineering of LBM parts, the fatigue strength of thermally sprayed additively manufactured substrates has not been in the focus of research to date. Thus, this study aims at evaluating the effect of different pretreatments onto 316L substrates processed by LBM prior to the deposition of a high velocity oxy-fuel (HVOF) sprayed WC-Co coating and their effect on the fatigue strength. Therefore, the 316L substrates were examined in their as-built state as well as after grit blasting with regards to the surface roughness, strain hardening effects, and residual stresses. To differentiate between topographical effects and residual stress related phenomena, stress-relieved 316L substrates served as a reference throughout the investigations. The WC-Co coated and differently pre-treated 316L substrates were mechanically tested under quasi-static and dynamic load conditions. Besides the fatigue strength, fatigue crack propagation characteristics as well as fracture mechanism were identified on the basis of fracture surface analysis. |