Effect of the filler metals on aluminium alloy joints

One of the most favored welding techniques of high strength aluminium alloy is commonly metal arc welding (MAW) process due to its high productivity and relatively low production cost. Apart from other process parameters (e.g. joint design) the filler material has a significant influence on the microstructure of the weld at the joint and consequently on the endurance limit of the end-product. The above considered process was used to weld AA6082 aluminum alloy using two different filler metals, Al4043 and Al5356 respectively. In this paper morphological, compositional analysis and mechanical characterization of the welded joints will be reported. Firstly, typical transverse sections of the weld joints samples have been observed using optical and scanning electron microscopy. The chemical composition at the interface has been monitored by energy dispersive X-ray spectroscopy. Secondly, orthogonal to the welding direction tensile tests have been performed aiming to provide both qualitative and semi-quantitative measures of the joint strength and its behavior. Impact energy of the weld joints and the microhardness values have been measured using a microindentation hardness tester with a load of 10 g and a load time of 15 s. Thirdly, fracture surface analysis has been realized by scanning electron microscopy. Welding with Al5356 presents superior characteristics.