Determination of the tensile behavior at middle strain rate of AA6061-T6 aluminum alloy welds

This paper is concerned with the effect of strain rate on the tensile properties of 6061-T6 aluminum alloy welds obtained by a novel welding method called the modified indirect electric arc technique. Experimental impact tests in welded joints and base metal were carried out by means of an inertial flywheel at a constant speed of 10 m s−1. From the force-time evolution, dynamic behavior and impact fracture energy were determined in the case of base metal and welded joints. Additionally, by means of an ultra-high speed camera synchronized to the force signal, and employing digital image correlation method and monitoring markers, the true strain-time curves were obtained. These results enabled determination of the stress-strain behavior under dynamic conditions for the base metal and welded joints, which, in turn, were compared with those reported in quasi-static conditions. The strain rate does not have a strong influence on the mechanical properties of yield and tensile stress, contrasted with energy absorption capacity, which increased significantly. Finally, the effect of strain rate on the fracture surfaces was investigated.