Microstructure and properties of laser clad WC/TiC/Co coating on YG8 cemented carbide surface
Liang Weiyin, Liang Guoxing, Dong Lijun, Liu Donggang, Wang Shiying
2021, 46(12):
168-174.
doi:10.13251/j.issn.0254-6051.2021.12.027
Abstract
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WC/TiC/Co coating on YG8 cemented carbide surface was prepared by laser cladding, and the microstructure and the phase composition were analyzed by means of scanning electron microscope(SEM), energy disperse spectroscopy(EDS) and X-ray diffraction(XRD), respectively. In addition, microhardness, hardness distribution and wear resistance were measured or tested. The results show that the coating surface is flat and bonded to the matrix tightly, the cross section morphology is fine without obvious defects. WC particles can be find in surface layer and edges while disappear in clad layer, and new homogeneous microstructure is observed in clad layer. In heat affected zone, WC grains take place recrystallization and gather because of heat effect of laser. The phases in clad layer are mainly composed of WC, W2C, (Ti,W)C1-x, M6C(Co4W2C, Co3W3C), etc, which result in dispersion strengthening, greatly enhance the performance of the coating. After detection, the microhardness of the clad layer distributes in the range of 1700-1800 HV0.5, and the maximum reaches 1783 HV0.5, which is obviously higher than the common YG8 cemented carbide, while the microhardness of heat affected zone and matrix is slightly decreased. Wear resistance of the clad layer is heightened effectively, compared with the YG8 cemented carbide, wear volume is reduced by 90.67%, average friction coeffiaiont is 0.293, and the abrasive wear is major wear mechanism.