TWI

With regard to the occurrence of coarse alpha-Al dendrites, eutectic phase, shrinkage porosity and other defects in cast aluminium alloys, an investigation was undertaken into the influence of different combinations of friction stir processing (FSP) and heat treatments on the microstructure and corrosion properties of cast A356 alloys (Al, 7.04%Si, 0.41%Mg). FSP was conducted using a threaded pin made from H13 mould steel at a rotational speed of 1000 rpm, travel speed of 65 mm/min and tool tilt angle of 2.5 deg. The heat treatment applied during experiments included artificial ageing (170 deg.C for 6 h) and solid solution ageing (540 deg.C for 4 h, water quenching and 170 deg.C for 6 h). Corrosion performance was assessed by polarisation curve tests and intergranular corrosion experiments. The microstructures of the stir zone, thermomechanically affected zone, HAZ and shoulder affected zone were examined before and after solid solution and ageing processes.

11th International Symposium, 17-19 May 2016, Session 4B: FSP, Paper 03