| Popis: |
The Ni-based WC alloy coatings were successfully fabricated on NAK80 mold steel by Nd:YAG and CO2 lasers. The microstructure and properties of the laser cladded coatings were analyzed by SEM, EDS, XRD and microhardness tester. The results show that phase constituents of both coatings are mainly composed of tungsten carbide (WC+W2C), Cr23C6, NiCr, CrB2 and γ-Ni. The excellent metallurgical bondings have formed at the interface between the substrate and the laser cladded coatings. Dendrite and white and block WC phase were observed in two kinds of laser cladded coatings, but the dendrite in Nd:YAG laser cladded coating is more fine. The microhardness of NAK80 mold steel is greatly improved by laser cladding, however the microhardness of the CO2 laser cladded coating is even higher than the Nd:YAG laser cladded coating. |
