Effects of Rare-Earth Oxides on the Microstructure and Mechanical Properties of Regenerated Cemented WC-12Co-2Ni Carbide

The effect of La2O3 and Y2O3 additions on the improvement of regenerated cemented carbide properties was investigated. The WC-Co powder recycled by the zinc melting method was used as a raw material, and five alloys were prepared by conventional powder metallurgy process by adding La2O3 and Y2O3 with 0, 0.3, and 0.6 wt.%, separately. The results show that they have a certain effect on the carbide compactness, but it is not obvious. When the La2O3 or Y2O3 content is less than 0.3 wt%, the hardness of regenerated cemented carbide will be slightly increased and then significantly decreased. A rare-earth oxide exhibits significant improvement of fracture toughness and transverse rupture strength, and the performance of carbide with Y2O3 is better than that with La2O3. When 0.3 wt.% Y2O3 is added, integrated mechanical properties of regenerated cemented carbide are excellent: hardness is 1720 HV30 kgf, fracture toughness is 8.41 MPa ·m1/2, and rupture strength is 1653 MPa.