Effects of WS2 and Ti3AlC2 additions on the high temperature wear properties of laser cladding YW1/NiCoCrAlY tool coating

Abstract In order to improve the wear resistance of shield machine tools, WS2 and Ti3AlC2 reinforced YW1/NiCoCrAlY tool coatings were fabricated on T-4241 high-speed steel by laser cladding (LC). The morphologies, elements and phases composition of obtained coatings were analyzed using an ultra–depth of field microscope (UDFM), scanning electron microscope (SEM), energy dispersive spectroscope (EDS) and X–ray diffraction (XRD). The effects of WS2 and Ti3AlC2 additions on the microstructure and high temperature wear properties of YW1 coating were investigated. The results show that there are no cracks on the coating surfaces and cross-sections, indicating that NiCoCrAlY bonding layer (BL) has a good adhesion effect. In addition, the coating grains are cellular crystal, equiaxed dendrite and spherical WC particles. The microhardness of YW1, YW1-WS2 and YW1–Ti3AlC2 coatings are 1113 ± 52, 1005 ± 54, and 1042 ± 36 HV1, respectively. After WS2 and Ti3AlC2 additions, the COFs of coatings are reduced by 20.9% and 39.1%, respectively, and the corresponding wear rates are reduced by 35.1% and 65.4%, respectively, showing that the self-lubricating phases significantly improve the high temperature wear resistance of YW1 coating. The main wear mechanism is adhesive wear, while oxidative wear and abrasive wear accelerate material loss. The YW1–Ti3AlC2 coating forms a continuous self-lubricating film during the wear process, resulting in the best high temperature wear resistance.