Microstructure and wear resistance of laser clad Ti₅Si₃/ (NiTi₂+β+Ti₅Si₃) composite coating

To improve the dry sliding wear resistance of titanium alloy, a wear resistant Ti₅Si₃ reinforced intermetallic composite coating was fabricated on the substrate of titanium alloy BT19 by laser cladding using the Ni-Ti-Si alloy powders. The composition and the microstructure of the intermetallic composite coating was investigated by OM, SEM, XRD and EDS. The wear resistance of the coating was tested under the dry sliding wear condition at room temperature. The results indicate that the laser clad composite coating is free from porous and microcracks and has a rapidly solidified homogeneous microstructure consisting of Ti₅Si₃ primary particles uniformly distributed in the NiTi₂-β-Ti₅Si₃ eutectic matrix. The laser clad Ti₅Si₃/ (NiTi₂+β+Ti₅Si₃) composite coating has high hardness and excellent wear resistance under dry sliding wear test conditions.