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In relation to the development of a friction stir welding (FSW) process to seal copper canisters for nuclear fuel waste, an investigation was undertaken into material and heat flow in FSW copper plates (thickness 50 mm) by inserting brass rods into the weld zone before joining to act as a marker material. The cross-sectional microstructure of welded specimens was observed by optical microscopy after milling, polishing and etching the surface in small steps over the weld line. A 3D finite element model was used to describe mass and momentum transport as well as heat transfer. The temperature distribution around the tool at different levels below the shoulder and flow velocity fields around the rotating pin were studied. The occurrence of a nugget with onion rings is discussed.

7th International Symposium, 20-22 May 2008, 4B: Non Ferrous, Paper 03