Structure And Performance Of Fsw Joint Of AZ31 And 5083 Alloy

Friction Stir welding is a new solid-state connection technology, which can effectively avoid drawbacks, appeared during fusion welding, such as crack and blowhole.By choosing optimal welding parameters including the tool's rotational speed, welding velocity and tool's geometry, friction stir welding of 5083 aluminum alloy and AZ31 magnesium alloy were conducted. The microstructures, microhardness, tensile properties and fracture of joints were investigated.The result indicated:Under the optimal welding parameters( the rotation speed is 800r/min, the welding speed is 100mm/min), the tensile strength of FSW 5083 butt-joint achieved 94.5% or so of that of parent metals, and when the rotation speed is 600r/min, the welding speed is 40mm/min) AZ31 butt-joint achieved 82.0% or so of that of the parent metals. Using AZ31 magnesium alloy wire in 5083 aluminum alloy plate for welding, surfacing layer and the base metal fusion bad and there were no visible penetration; using 5356 wire in AZ31 magnesium plate can get a certain fusion deep, and when welding two layers get the maximum penetration. The weldability between 5083 and AZ31 was also poor by FSW, trench and tunnel-type defects were generated. The fluctuation of hardness in FSW weld of dissimilar metal was large due to intermetallic compounds. The defects were attributed to unreasonable welding parameters and the existence of the intermetallic compounds, which had a very negative impact on its mechanical properties, especially ductility.