TWI

Similar and dissimilar joints between 2014-T6 (Al, 4.67%Cu) and 6061-T6 (Al, 0.9%Mg, 0.63%Si) aluminium alloys were fabricated by friction stir welding (FSW) with various sets of process parameters, and the microstructure and mechanical properties of the welded joints were investigated. FSW was performed using a HERMLE milling machine with a scrolled shoulder tool and a threaded pin, and welding experiments were conducted at a rotational speed of 500 or 1500 rpm and a travel speed of 90 mm/min. Other parameters varied were the lateral offsets of the tool towards the 2014 alloy and alloy position (advancing or retreating side). The forces and torque applied to the tool during welding were measured. Microstructure was observed by optical microscopy, SEM and energy-dispersive X-ray spectroscopy. Mechanical properties were characterised by transverse tensile tests. Issues discussed include onion-ring shaped nugget structures and the importance of the relative mechanical strengths of the alloys at high temperature.

9th International Symposium, 15-17 May 2012, Session 10B: Non Ferrous, Paper 02