Effect of welding process on microstructure, mechanical properties and corrosion behavior of AA2519 Al-alloy Available to Purchase

By lowering the copper with a tiny amount of Mg, AA2519 emerged as an upgrade version of AA2219 Al-alloy. The modification is intended to improve the ballistic resistance and strength to weight ratio. Despite its improved properties, it was facing some problems due to welding. Formation of oxide layers, solidification cracking, and porosity are the significant problems raised during welding. Given the above, the present work is planned to investigate the effect of the welding process on microstructural changes, corrosion behavior, and mechanical properties of AA2519 Al-alloy. Gas Tungsten Arc Welding (GTAW) and Friction Stir Welding (FSW) were used in the present work to weld 10mm thick plates of AA2519 Al-alloys. Microstructure and hardness in as-welded conditions were studied. Potentiodynamic polarization tests were conducted in the aqueous solution of 3.5% NaCl aerated environment to explore the pitting corrosion behavior. Exfoliation corrosion studies are carried out for various time lapses with EXCO solution. The work showed better corrosion resistance and mechanical properties of AA2519 FS welds when compared to that of GTA welds. Insulation paths of galvanic cell formation between Al₂Cu and α-Al matrix are provided due to undissolved strengthening precipitates like Al₂CuMg, Al₃Zr, and Al₃Ti was found to be the mechanism for a better combination of hardness and corrosion resistance.