TWI

An experimental investigation was undertaken to study the effects of different pin profiles (threaded conical, square, pentagon and hexagon) and the same process parameters on temperature distribution around the tool and resulting microstructure during friction stir processing (FSP) of 7075 aluminium alloy (Al, 5.1-6.1%Zn, 2.1-2.9%Mg, 1.2-2%Cu). FSP was performed with a vertical milling machine at a tool rotational speed of 765 rpm, traverse speed of 31.5 mm/min and tool tilt angle of 2 deg. K-type thermocouples were used to monitor the temperature on advancing and retreating sides. Thermomechanically affected zone (TMAZ) and stir zone microstructures and grain boundaries were observed by optical microscopy. Vickers hardness measurements were carried out under a load of 300 g and a dwell time of 10 s.

11th International Symposium, 17-19 May 2016, Session 6B: Techniques II, Paper 01