Thermal Shock Resistance Of Cemented Carbides With High Binder Phase Content: Comparison Between Co And Co-Ni-Cr Based Binders

The damage induced by repeated quenching experiments in WC-43 vol.%Co and WC-40.7 vol.%CoNiCr cemented carbides is characterized by the growth of microcracks at the WC-metallic binder interface. For the WC-43 vol.%Co alloy, crack growth is only detected at 700ºC, whereas for the WC-40.7 vol.%CoNiCr material this starts at 400ºC. Comparison of results obtained with prismatic and cylindrical samples, show that thermal shock results are strongly affected by the geometry of the test specimens in the case of the WC-40.7 vol.%CoNiCr alloy, but not for the WC-43 vol.%Co grade. This is likely related to their differences in toughness.