Effect of milling temperature on the synthesis and consolidation of nanocomposite WC-10Co powders

The effect of milling temperature on the synthesis of WC-10Co powders was investigated by mechanical alloying carried out at −30 °C and room temperature (RT). X-ray diffraction (XRD) showed that WC domain size was reduced to 26 nm after 1 h cyclic milling at −30 °C and 21 nm after 1 h RT milling. The morphology of the milled powders was determined by scanning electron microscopy (SEM) and this showed that particles from −30 °C milling had increased deformation and less irregularity. Differential scanning calorimetry (DSC) of the low temperature milled powder showed a greater enthalpy release. The powder milled at −30 °C exhibited a relative density of 65.5% after cold compaction at 400 MPa pressure compared to 64% for the RT milled powder. Both powders were consolidated by using pressureless sintering and sinter-HIP techniques. The powders milled at −30 °C and RT achieved a maximum hardness of 13.5 GPa and 12.7 GPa, respectively.