Master sintering curve of nanocomposite WC-MgO powder compacts

The master sintering curve (MSC) of nanocomposite WC-MgO was constructed based on the combined-stage sintering model. Nano-sized WC-4.3wt%MgO powder with an average particle size of 35 nm was synthesized by high-energy ball milling and then pressed uniaxially at a pressure of 500 MPa to fabricate green compacts. The shrinkage response of the compacts during heating was studied by dilatometric runs at constant heating rates of 5 and 10 °C/min up to 1900 °C. The master sintering curve with sintering activation energy Q = 361.8 kJ/mol was constructed between 600 and 1900 °C. The MSC was validated by isothermal and non-isothermal sintering experiments with identical green compacts. The results demonstrate that the MSC can be successfully applied to predict and control densification evolution during heating, regardless of the heating path, and non-isothermal sintering in the high-temperature range.

► We investigated the densification process of nanocomposite WC-MgO powders compacts. ► The apparent activation energy for WC-MgO compacts was calculated as 361.8 kJ/mol. ► The shrinkage levels and final densities were predicted using the constructed MSC. ► A deviation between predicted and experimental results at low temperature was found.