Joining dissimilar aluminum alloys and other metals and alloys by friction-stir welding

A wide range of aluminum alloys and other metals and alloys. particularly dissimilar materials, have been friction-stir welded in this study. These include Al 5052/Al 7075, Al 7075/Al 2017, Al 5052/Al 2017, Al 7x1x(Sc)/Al 7x5x(Sc), Cu/brass. and 6061 Al with a thin Cu sheet in the butted seam to observe particulate flow in the dynamically recrystallized regime which facilitates solid-state welding. A 62Be38Al powder metallurgy composite was also friction-stir welded and in contrast to degradation of the weld in some systems by as much as 60%, the weld zone hardness increased by more then 40% as a consequence of recrystallization and homogeneous mixing of hard, fine Be grains and At binder grains. Differences in recrystallization and material flow to create a weld are examined by microstructural observations involving light metallography and transmission electron microscopy.