Mechanical properties of friction stir welded 2024 aluminum alloy and precipitated phases in stir zone

摘要

2024 aluminum alloy sheets in T4 temper were welded successfully by friction stir welding (FSW) technique. When the welding travel speed was 300 mm min(-1), tensile strength reached a maximum value (294 MPa). The precipitated phase is mainly metastable U(A1CuMg) of reinforced phases in thermo-mechanically affected zone (TMAZ). Lots of the A1Cu(3) black particles precipitated on the grain boundary of TMAZ. However, a large number of Cu2Mg black granular precipitates were observed in the WN region.