Study on the Heat-Affected Zone, Microstructure, and Surface Quality of TB8 Titanium Alloy Treated by Laser-Assisted Micromachining

TB8 titanium alloy has good comprehensive properties and has been widely used in the aerospace field. In this paper, the laser-assisted micromachining (LAMM) of TB8 titanium alloy was carried out to study the influence laws of laser beam power and laser scanning speed on the laser heat-affected zone (HAZ) and establish the finite element temperature field model. The experimental results of conventional machining and LAMM were compared. The effects of laser beam power, cutting speed and cutting depth on microstructure, surface microhardness, and surface residual stress of TB8 titanium alloy were studied and analyzed. The experimental results show that the laser HAZ depth and width decrease with the increase of cutting speed and increase with the increase of laser beam power. The simulation has a good correlation with the experiment, which proves the correctness of the simulation. The LAMM can reduce the grain breakage of the machining profile. With the increase of cutting depth and laser beam power, the grain breakage decreases first and then increases, and the cutting speed is the opposite. When the cutting speed is 50 mm/s, the maximum improvement is 16.9%. The LAMM can reduce the surface residual compressive stress and improve the surface hardness of the workpiece.