Effects of ball milling time on the synthesis and consolidation of nanostructured WC-Co composites

The effects of ball milling time on the synthesis and consolidation of WC-10 wt%Co powder were investigated by high energy milling in a horizontal ball mill. Nanostructured powder was mechanically alloyed after 60 min cyclic milling with a WC average domain size of 21 nm. The number of nanosize (<0.2 μm) particles increased with milling time. Contamination by Fe increased with milling time, reaching almost 3 wt% after 300 min milling. The onset of the WC-Co eutectic was lowered to 1312 °C through an increase in milling time. The density of the compacted powders increased with the compaction pressure but decreased with milling time achieving 61.7% after 300 min milling compared to 64.4% for 30 min. The compressibility behaviour of the milled powders was determined using a compaction equation. Densification and hardness reached optimum levels for the 60 min milled powder after both pressureless sintering and sinter-HIP.