TWI

Butt joints were fabricated in AA 6061-T6 (Al, 0.8%Mg, 0.6%Si) and AA 6082-T6 (Al, 0.62%Mg, 0.99%Si, 0.49%Mn) plates (thickness 6 mm) by friction stir welding, and the tensile and fatigue properties of the weldments were investigated. The microstructure of the welded joints was observed by optical microscopy. Tensile tests were conducted according to the ISO 6892-1:2009 standard. Axial stress-controlled fatigue tests were performed at room temperature using a resonant testing device at a frequency of 100 Hz. Specimens were also characterised by Vickers hardness measurements and optical fatigue fracture surface observations. Issues discussed include joint efficiencies with respect to tensile strengths, the relationship between fatigue lives and crack initiation sites, the surface galling of weld surfaces, and a comparison between the fatigue strengths of production and laboratory weldments.

9th International Symposium, 15-17 May 2012, Session 3A: Weld Performance, Paper 01