Effect of Heat Treatment on Corrosion behavior for Friction Stir Welding of aluminum alloys AA 2024- AA 6061

Abstract

This work aims to study the effect of aging heat treatment of friction stir welding of aluminum alloys AA 2024- AA 6061 on corrosion behavior. The dimensions of aluminum alloys plates which used are 85mm, 150 mm and 6mm as width, length and thickness respectively. The welding process was done using a milling machine and welding tool with cylindrical shape (18mm and 6mm of shoulder and pin diameters respectively, with 5.8mm as a pin length). The welding process conditions were 1040 rpm and 30 mm/min as tool rotation speed and welding speed respectively. After the welding process, heat treatment process was conducted. The samples were heated to a temperature of 520 °C for 30 minutes followed by a cooling process in water, then, it has been aging at a temperature of 210 ?C for 4 hours. The microstructures of the samples of the base alloys and friction stir welding are examined by using optical microscopy and the corrosion test done by using a WENKING Mlab multi channels potentiostat and SCI-Mlab corrosion measuring system to plotted Tafel polarization curves in 3.5% NaCl solution. The results shown that the microstructure of the FSW sample after heat treatment has a finer uniform distribution precipitates and has high corrosion resistance