Material Characterization of Laser Remelted Aluminium Alloy for Improvement in Fatigue Life

Abstract

This study is carried out to study the microstructure of Aluminium Alloy. Aluminium is used widely in spacecraft, railway cars, bicycles, aircraft and automobiles. In CNC turning operations, machining conditions like feedrate, depth of cut and cutting speed severely affect surface roughness. In the research previously carried out, the specimens prepared on CNC Turning as per ISO 3685, the roughness of each specimen was measured. CO2 Laser was used on 3 different energy densities to melt the surface of the specimen from each combination of machining conditions. Carbon Black paste was used to enhance the absorption of aluminium. In this research work, laser remelted specimens of Aluminium 6061-T6 are cut by wire EDM (Electrical Discharge Machining). The specimens are then cold-mounted and are grinded on different grades of grinding paper and are polished on several pads. All the specimens are prepared on different machining conditions and the surface of the specimens are checked by optical microscope in order to check the porosity on the specimen after being laser treated. The surface crack propagation and surface quality of the laser treated specimen on the center and the corner of the work piece were checked. The Vickers micro hardness test also was performed to define the differences on the center and corners of laser treated specimens to the machined surface. Moreover the change in trend of hardness of the laser remelted material is observed.