Comparative Study of Surface Integrity for AZ31B Magnesium Alloy during the Application of Ultrasonic Vibration and Laser Energies in the Turning Process

AZ31B magnesium alloys are significant materials for biomedical, aviation, and automotive industries. But, the poor surface properties of AZ31B magnesium alloys limit their usage for wider applications. Literature suggests that hybrid machining processes have achieved better machining performance compared to the conventional turning (CT) process without using any cutting fluids. Therefore, an attempt has been made to improve the surface integrity of AZ31B magnesium alloy in terms of machining forces, machining temperature, chip morphology, surface roughness, surface damage, microstructure, microhardness, residual stresses, and corrosion behavior during a recently developed hybrid machining technology, i.e., ultrasonic-vibration-laser-assisted turning (UVLAT). A comparative surface integrity analysis has been carried out among the CT, ultrasonic vibration-assisted turning (UVAT), laser-assisted turning (LAT), and UVLAT processes. The results of the current study indicate significant benefits of the UVLAT process on surface integrity. Machining forces and surface roughness were reduced by 42-61% and 18-33%, respectively, for the UVLAT process than the other processes. However, the machining temperature was increased by 8-83% during the UVLAT process compared to the other processes. Ductile chips, smooth surface, and higher grain refinement were obtained in the UVLAT process when compared with other processes. Residual stresses were found more compressive in nature for the UVLAT process than that of the other processes. Microhardness and corrosion resistance were increased by 28-106% and 13-56%, respectively, during the UVLAT process in comparison with the other processes. This might be ascribed to the frequent tool separation and workpiece material thermal softening, simultaneously. The UVLAT process can be beneficial for diverse applications due to the improvement in surface properties.