Machinability and surface integrity analysis of magnesium AZ31B alloy during laser assisted turning

Abstract

Abstract: Magnesium AZ31B alloys are promising materials for biomedical, aviation, and automotive industries. Severe plastic deformation processes such as machining processes have shown capabilities to improve the performance of magnesium AZ31B alloys. However, the usage of water and oil-based coolants during the machining of magnesium AZ31B alloys generates hydrogen and hazardous gases, which can explode and create a hazardous environment for nature and human beings. Therefore, machining without using any coolants has been preferred to machine magnesium AZ31B alloys. Moreover, laser assisted turning (LAT) has emerged as a hybrid machining process to machine various materials without using any coolants and in an eco-friendly manner. Hence, an attempt has been made to analyze the machining performance of magnesium AZ31B alloy during the LAT process. In this study, the machinability and surface integrity of magnesium AZ31B alloy was compared for LAT and conventional turning (CT) processes. With the usage of laser, a substantial decrement in machining forces, surface roughness, and tool wear was achieved during LAT than CT. Though, the machining temperature was obtained to be higher for LAT in comparison to CT. Long, continuous, and ductile chips were formed in LAT. Lesser scratches, cracks, and pits were observed on the machined surface during LAT than in CT. Coarse grain microstructure was observed for both CT and LAT. However, lower microhardness was obtained in LAT than in CT. Compressive residual stresses were achieved for LAT than tensile residual stresses in CT. Corrosion resistance was enhanced by up to 50 % for the LAT process than in the CT process.