Friction stir welding of dissimilar aluminium alloys 2219 to 5083

Abstract

Aluminium alloys with small amounts of copper magnesium silicon manganese and other elements have very useful properties and are used as structural materials Al Cu alloy 2219 and Al Mg alloy 5083 are two widely used alloys in aerospace and marine industries AA2219 is age hardenable and exhibits good strength at elevated as well as cryogenic temperatures It also exhibits acceptable corrosion resistance It has excellent weldability characteristics However the weld zone of the AA2219 fusion welds softens due to melting of the strengthening precipitates and its joint strength is only about 40 compared to that of the base material in T87 condition The fusion welds also exhibit poor ductility AA5083 is an alloy with moderate strength excellent corrosion resistance and low cost used extensively in commercial marine applications A magnesium content of about 4 5 provides good strength and high corrosion resistance to sea water An important issue in the fusion welding of aluminium magnesium alloys is the vaporization of magnesium The selective vaporization of magnesium from the weld metal causes lowering of mechanical properties and corrosion resistance of the welds