TWI

Friction stir welding (FSW) experiments were undertaken on stacked laminates of pure copper and 60/40 brass (60%Cu, 40%Zn) to investigate material flow patterns and microstructural changes during welding. FSW was conducted using a threaded MX Tri-flute tool made from Nimonic 105 alloy at rotational speeds of 200-400 rpm and traverse speeds of 100-300 mm/min. Flow visualisation was achieved by observation of colour differences between the dissimilar materials. Microstructural changes in different areas of the friction stir zone were observed by SEM with secondary or backscattered electrons and energy dispersive X-ray analysis. Microhardness tests were performed using a Mitutoyo MVK-H1 with a Vickers diamond indenter, and welded joint strength between copper and brass was determined by 3-point bend testing. Flow patterns and microstructural characteristics in the plunge zone, transitional zone and steady state weld zone are discussed.

9th International Symposium, 15-17 May 2012, Session 10B: Non Ferrous, Paper 04