Microstructure Evolution during Friction Stir Welding of Aluminum Alloy AA2219

EBSD study on microstructure and texture of friction stir welded AA5052-O and AA6061-T6 dissimilar joint

“…In NZ,due to the continuous absorption of dislocations leaving misorientation of LABs increased, LABs gradually transformed into HABs whose nucleation mechanism was continuous dynamic recrystallization [8], so that the number of HABs gradually increased, while the number of 2-12°grain boundaries reduced, which resulted in refinement of the grains. Original grain boundaries of LABs were eliminated by migration, continuous dynamic recrystallization led to the formation of fine and equiaxed microstructure in NZ [30]. Fig.…”

Evaluation of the gap area between two sided friction stir welding of AA 2024-T351

“…In FSW aluminum joints four zones are clearly shown: the Nugget Zone (NZ) is created by the penetrating tool pin and characterized by a recrystallized microstructure containing very fine grains, which are formed as a result of the severe plastic deformation and high temperatures (Figure 2-c) surrounded by the Thermomechanically Affected Zone (TMAZ) (Figure 2-b) is characterized by a highly deformed structure. A distinct boundary between the NZ and TMAZ is seen on the advancing side, unlike the unclear demarcation on the retreating side [1,[4][5][6]. Consequently, it can be said that, microstructural changes in TMAZ are driven by the combined influence of heat generated and deformation induced by the tool and the Heat Affected Zone (HAZ) on either side of the joint line.…”

“…But the loss of strength in the components fabricated from these alloys using the conventional fusion welding techniques, poses a serious limitation in their utilization for these purposes [1]. Usually, most of the fabricated components and structures are of welded construction and the problems associated with the fusion welding of these aluminum alloys, like porosity, slag inclusion, solidification cracks, and distortion, deteriorate the weld quality and the resultant joint properties [2].…”

Effect of pin offset on the mechanical properties of friction stir welded AA 6013 aluminum alloy plates

“…Lower cooling rates are obtained in the stir zone in comparison to those of other regions, namely heat affected zone and thermo-mechanically affected zone. The cooling rate is evaluated to be the driving force for grain growth during the recrystallization process, and for a plastic deformation at a sufficient temperature, the dynamic recrystallization simultaneously runs and makes grains recrystallize with slow cooling rate [50][51][52][53]. As mentioned above, friction stir welding applications were performed on a backing plate and this plate acted as a heat sink.…”