Mechanisms of plastic deformation of WC–Co and Ti(C, N)–WC–Co

Microstructural changes during wear by plastic deformation of cemented carbide and cermet cutting inserts

“…It has previously been shown that Co segregates to WC/WC grain boundaries in WC-Co materials, [38,39] and this was also found in the LC and HC cermets. Figure 12 shows compositional profiles, measured by TEM-EDX, across g/g boundaries in the HC and LC cermets.…”

“…[39] From these measurements, it can be seen that the materials had two transitions from brittle to ductile and from ductile to highly plastic behavior with increasing temperature. The transition temperatures for the WC-Co material (800°C and 1000°C, respectively) were lower than for the cermet (1000°C and 1200°C, respectively) and, thus, the HC cermet should be expected to have a better PD resistance than the WC-Co.…”

“…Tests were performed at temperatures from 750°C to 1200°C and showed larger strains of the WC skeleton before fracture compared to the cermet skeleton. [39] The presence of slip bands in the WC suggests that there is a smaller difference between the activation energies for dislocation glide and climb in WC compared to the cermets. Hence, the rate controlling mechanisms may vary between different parts of the material.…”

Grain and phase boundary segregation in WC–Co with small V, Cr or Mn additions

“…This suggests that this phase grows when the material is cooled after sintering. The strength of the WC/WC grain boundaries is very important when using cemented carbides [15]. Co segregation was observed to all studied WC/WC grain boundaries.…”

“…During high-speed cutting the load and temperature may become so high that the WC skeleton breaks up by Co grain boundary infiltration, thus making grain boundary sliding possible [15]. For this reason, strengthening of the WC/WC grain boundaries would be beneficial.…”