TWI

Friction stir lap diffusion welding was employed to fabricate dissimilar AA 6060 aluminium alloy/mild steel joints and mechanical testing and metallurgical examination of the weldments were undertaken to investigate the effect of microstructure formation at the interface on fracture strength. Welding experiments were performed at rotational speeds of 1000 or 1400 rpm and a traverse speed of 80 mm/min using a milling machine and tools made from H13 tool steel. Microstructure was observed by optical microscopy and SEM. Mechanical properties were characterised by tensile-shear tests. Issues discussed include the influence of the distance between the bottom of the pin and the bottom steel plate on interfacial diffusion, intermetallic formation and fracture strength, and the occurrence of ductile fracture in specimens with a continuous interfacial intermetallic layer.

9th International Symposium, 15-17 May 2012, Session 4A: Variants I, Paper 02