Effect of Laser Power on Microstructure and Properties of CBN Coating by Laser Cladding on TC11 Titanium Alloy

A wear resistant coating is fabricated on TC11 titanium alloy by laser process using CBN powder as the preset materials. Microstructure, microhardness and wear properties of the coating are characterized by optional microscope (OM), scan electron microscopy (SEM), X-ray diffraction (XRD) and HV-1000 microhardness tester and the effect of different laser powers (1.2kW, 1.6kW, 2.0kW) on the three factors was studied. The experiment results show that the coating microhardness and wear resistance increases firstly and then decreases with the increasing of laser powers when the other parameters are fixed. when the laser power is smaller, the laser energy is smaller, the life of molten pool is shorter, the pores can’t discharge in time induced CBN ceramics can’t formed evenly and the interface bonding strength of coating and substrate was weak; when the laser power is bigger, the laser energy is bigger, the CBN particles can dissolved sufficiently, no crack and pores formed at the coating, but can’t obtain coating reinforced by CBN particles due to the CBN particles dissolved mostly. When the laser power was 1.6kw, the clad coating is smooth and the CBN particles distribute evenly, the microhardness reaches maximum value and the wear resistance is the best. The microhardness was up to 4200HV.