TWI

A cantilever type rotary bending fatigue testing machine with high speed loading capability was employed to investigate the high cycle fatigue properties of the stir zone, thermomechanically affected zone and HAZ in friction stir welded joints of various aluminium and magnesium alloys. The materials studied were A5083-O (Al, 4.52-4.9%Mg, 0.64-0.66%Mn) and A6005C-T5 (Al, 0.66-0.67%Mg, 0.57-0.59%Si) aluminium alloy rolled and extruded plates (thickness 8 or 20 mm) as well as AZX 611 magnesium alloy (Mg, 5.93-6%Al, 0.56-0.98%Zn) extruded rods and plates. Friction stir welding was conducted at a tool rotational speed of 800-2000 rpm, plunge depth of 0.1 mm and dwell time of 10 s. Weld zones were identified by Vickers hardness distribution measurements and cross-sectional microstructure observations. Cantilever type rotary bending and axial loading fatigue test results were compared with respect to the influence of surface roughness and testing method on S-N curves and fatigue life.

12th International Symposium, 26-28 Jun 2018, Session 8B: Dissimilar, Paper 02