TWI

Dissimilar lap joints between AA 6061-T6 (Al, 1.01%Mg, 0.59%Si) and A356 (Al, 7.02%Si) aluminium alloys were fabricated by friction stir welding (FSW) and the influence of process conditions on joint microstructure evolution and mechanical properties was investigated. Lap welding experiments were conducted using an FSW-3LM-4012 machine at a tool rotational speed of 800-1200 rpm and a travel speed of 100 mm/min. Microstructure evolution during FSW was observed by optical microscopy and SEM, while grain and particle size distributions were determined with quantitative image analysis. Mechanical properties were characterised by Vickers hardness measurements and shear tensile tests. Issues discussed include recrystallisation grain size distribution and intermetallic precipitates in the welding nugget, kissing bond defects and the effect of heat input on shear strength.

11th International Symposium, 17-19 May 2016, Poster Session, Paper 09