TWI

Friction stir welding experiments were undertaken on commercial SPF (superplastic forming) AA 5083-H19 (Al, 4.43%Mg) and AA 2004 (Al, 6.05%Cu) aluminium alloys, and the effects of tool size, geometry and primary process variables on microstructure and mechanical properties were investigated. Various tools were used to fabricate the welds, incorporating Concave, "Triflute", "Triflat", Large shoulder and GSP 5651 designs. Spindle speed and traverse speed were varied between 500-700 rpm and 175-746 mm/min, respectively. Welds were tested as-made or after annealing at 350 deg.C. In addition to bead on plate welds, some butt joints were welded. Problems with set-up and plunge depth tolerance were encountered. Microstructure was observed by optical microscopy and SEM. Mechanical properties were characterised by tensile tests and microhardness measurements. Cone testing was conducted to determine the superplastic properties of the material.

7th International Symposium, 20-22 May 2008, 5B: Friction Stir Processing, Paper 04