TWI

Dissimilar joints between 2017A-T451 (Al, 4.14%Cu, 0.72%Mg, 0.68%Si) and AlSi9Mg (Al, 8.6%Si, 0.64%Fe, 0.34%Mn, 0.31%Mg) aluminium alloys were fabricated by a friction stir welding process featuring different rates of rotation of the pin and shoulder (1400 rpm and 350 rpm, respectively). Butt welds were made parallel to the rolling direction of 2017A alloy sheets. MIcrostructures and surface conditions were observed by optical microscopy, TEM and SEM. Transverse cross-sectional hardness profiles were measured at a distance of 0.8 mm from the face of the welded joint. Issues discussed include intermixing between the two alloys, shrinkage defects and the effect of plastic deformation on cast alloy particle fragmentation.

10th International Symposium, 20-22 May 2014, Session 5A: Variants, Paper 02