Effect of Welding Parameters on Defects and Fracture Behavior of Friction Stir Welded 2195 T8 Al Li Alloy Joints
In this work, the ratio of rotation rate to advancing speed was fixed to 10 to fabricate friction stir welding (FSW) butt joints of 2195 T8 plates with 7.5 mm in thickness. The results revealed that the heat input of joints along the vertical direction varied with the welding parameters though these parameters had a same ratio. 500 50 and 600 60 joints failed in the thermal affected zone and thermal mechanical affected zone (TAZ/TMAZ) while other joints all failed in stirred zone (SZ) The hardness profile across the joints showed a similar W shape, while the hardness in bottom area increased with the increasing of parameters. Lazy S and kissing bond defects appeared in all of these joints, and over burn defect was also found in 1000 100 joint. It is concluded that the heat input distribution gradient during FSW across the joints becomes non uniform and a sudden change between upper and lower areas even occurs.