Abstract
The microstructure of the interface between Al alloy and Mg alloy joined by friction stir welding is characterized using electron microscopy. The intermetallic compound reaction layer has a thickness of about 1 μm and consists mainly of fine-grained Al12Mg17 phase. Further nanosize-grained Al3Mg2 inclusions in close proximity to the Al12Mg17 layer appear in the Al alloy.