Indentation fatigue of WC–Co cemented carbides

• Indentation fatigue of WC–Co systems was studied using instrumented indentation.
• Slip in WC and fracture of WC/WC bridges were dominant in system with higher CWC.
• Phase transformation of Co was dominant in the system with higher LCo.

Indentation fatigue of WC–Co systems with different microstructure parameters was investigated using instrumented indentation. A Berkovich indenter was used at maximum loads from 25 mN to 200 mN, then unloaded to 50% of the maximum load and repeatedly re-loaded to 100 cycles. FIB/TEM observations have been used for characterization of the deformation and damage mechanisms in the zone beneath the indenter to study the influence of microstructure parameters on fatigue and fatigue mechanisms. Deformation induced fcc–hcp phase transformation of Co binder was the main mechanisms in the system with higher volume fraction of binder and slip in WC grains and fracture of WC/WC bridges in the system with lower Co content and higher contiguity. These mechanisms result in different fatigue behavior of the systems.