Microstructures of Ni-Cr-Ti-Al laser claddings on K418 superalloy

Ni-Cr-Ti-Al cladding powders were mixed by using mechanical ball milling technique. Ni-Cr-Ti-Al laser cladding layers with different chemical composition on superalloy K418 were prepared by CO₂ laser. By means of optical microscopy (OM), scan electron microscopy (SEM) and X-ray diffraction (XRD), microstructures of cladding layers were studied, and micro-hardness was measured. The results show that, during the process of laser cladding, Ni₃ (Al, Ti), Ni₂TiAl, NiAl and Ni₃Ti intermetallic compounds are formed resulting from the interaction of Ti, Al and Ni. Microstructures of Ni-Cr-Ti-Al cladding layers are characterized by massive Ni₂TiAl, Ni₃Ti or NiAl distributing between Ni₃(Al, Ti) dendritic. Ni-Cr-Ti-Al laser cladding layer with the chemical composition of Ni66. HCr7. 35Til4. 39A112. 15 is beneficial to the diffusion bonding between TiAl alloy and K418 superalloy.