EXPERIMENTAL INVESTIGATION ON FRICTION STIR WELDING OF CRYOROLLED AA2219 ALUMINUM ALLOY JOINTS

Abstract

In this paper, experimental investigation on cryorolled aluminum AA2219-T87 plate by using friction stir welding (FSW) process is carried out. AA2219-T87 plates with a size of 200[Formula: see text]100[Formula: see text]22.4 mm were rolled and reduced to 12.2[Formula: see text]mm thickness (more than 45% of reduction in total thickness of the base material) at cryogenic temperature (operating temperature range [Formula: see text]90–[Formula: see text]30[Formula: see text]C). The cryorolled (CR) plates have reduced grain size, improved hardness and increased corrosion resistance property compared with the uncryorolled AA2219-T87 plates. FSW joints of cryorolled AA2219-T87 plates were prepared using cylindrical threaded FSW tool pin profile. Mechanical and metallurgical behaviors of friction stir welded joints were analyzed and the effects of the FSW process parameters are discussed in this paper. The variation of microhardness in the FSW joint regions were correlated with the microstructure of FSW joints. Cryorolled plate and FSW joints were tested for corrosion resistance using potentiodynamic polarization test. FSW joints shows better result during the corrosion resistance analysis compared to base AA2219-T87. The X-ray diffraction (XRD) test results showed that fine [Formula: see text]-Al grains with eutectic phase (Al2Cu) were present in the weld nugget (WN). The large clusters of strengthening precipitates were reduced in size and merged with the weld nugget portion.