Characterization and preparation of ultra-fine grained WC–Co alloys with minor La-additions

The ultra-fine grained WC–Co alloys with different lanthanum contents were prepared through sol–gel process and low pressure sintering. Effects of lanthanum on the microstructure and mechanical properties of WC–Co alloys were investigated using X-ray diffraction, scanning electron microscopy and mechanical testing. The results showed that trace La addition suppresses the formation of binder-enrichment structure on the sintered skin, decreases the WC grain size and the volume fraction of Co3W3C phase, and thus greatly improves the hardness and fracture toughness of the ultra-fine grained WC–Co cemented carbides.

► The authors first reported the ultra-fine grained WC–Co alloys with different lanthanum contents prepared through sol–gel process and low pressure sintering. ► Trace lanthanum addition suppresses the formation of binder-enrichment structure on the sintered skin and decreases the WC grain size and the volume fraction of Co3W3C phase. ► Trace lanthanum addition improves the hardness and fracture toughness of the ultra-fine grained WC–Co cemented carbides.