TWI

The effects of tool shoulder size and tilt angle on the formation of weld zones during the friction stir welding of aluminium alloys were studied. Aluminium alloy 5083 (Al, 4.2%Mg, 0.2%Si, 0.6%Mn, 0.15%Fe, 0.09%Cr, 0.09%Zn, 0.06%Cu, 0.02%Ti), an alloy commonly used in boat building, and aluminium alloy 6061 (Al, 0.9%Mg, 0.6%Si, 0.1%Mn, 0.33%Fe, 0.17%Cr, 0.02%Zn, 0.28%Cu, 0.02%Ti) were used in the experiments. The shoulder diameters of the steel tools were 20 and 16 mm. Tilt angle was 2 or 4 degrees. A small shoulder resulted in the formation of a channel type defect. A higher tilt angle resulted in a larger forging action and the channel type defect size was reduced. The use of alloy 6061 resulted in a larger plastic flow in the weld region and more complete filling that the use of alloy 5083.

5th International Symposium, 14-16 Sep 2004, Session 7B: Metallurgy/Microstructure, Paper 01