Effect of Binder Composition and Coating on Corrosion and Fatigue Damage of Cemented Carbides

E. PIQUE; M. ARCIDIACONO; J.J. ROA; S.N. SIMISON; J. GARCIA; A.D. SOSA

Thessaloniki

Conferencia; Euromat 2017; 2017

p { margin-bottom: 0.25cm; direction: ltr; line-height: 120%; text-align: left; }atigue Corrosion of Cemented CarbidesCracks normally occur during machining in interrupted cutting conditions (e.g., milling processes) in which cemented carbides are under thermo-mechanical cycling loads. In the presence of cooling media (wet machining) cemented carbides develop fatigue induced cracks parallel to the cutting edge; which lead to chipping and reduced tool life. The formation and propagation of these cracks is accelerated by chemical attack of the binder phase. A series of experimental techniques have been employed in order to understand the effect of microstructure and chemical composition on corrosion and fatigue damage of cemented carbides. The corrosion resistance in cooling fluid solution of cemented carbides with different binder alloys has been characterized by means of potentiodynamic anodic curves and the attack surfaces have been analyzed by SEM and EDS. Contact fatigue tests were done in dry and wet conditions and different crack types have been observed using SEM/FIB analysis. Additionally, some milling machining tests were done and the obtained cracks were evaluated by optical microscopy. Nanoindentation tests were performed in order to measure mechanical properties of the materials under dry, wet and polarized conditions. Nanoindentation experiments with cycling load were also performed but no cracks formed in the experimental conditions used.It can be concluded that the addition of Cr and (Ta,Nb)C to the WC-Co composition enhances corrosion attack resistance of the binder, which may reduce the formation of fatigue induced cracks in the presence of cooling media