Effect of laser parameter on microstructure and microhardness of NiCrBSi laser cladding layer

Laser cladding was performed on the surface of TC4 alloy with NiCrBSi. The microstructure of cladding layer was analyzed by SEM and XRD, and the microhardness was measured. The results show that the laser parameter has great effect on both microstructure and microhardness. The quality of laser cladding is determined by laser power, laser beam diameter and laser scanning speed. For a certain laser beam diameter, the higher the laser power is, the larger the power density will be. The heating time is dependent on laser scanning speed. With the increase of heating time, the cladding depth becomes larger. With the increase of diluting rate, the hardening particles of TiB₂ and TiC are formed in the claddings layer and the microhardness remarkably increases.