A feasible operational parameter window for enhancement of welding speed in friction stir welding of 2195-T8 Al–Li alloy

The improvement of the welding speed becomes extraordinarily difficult for the friction stir welding (FSW) of Al–Li alloys with medium thickness (5–10 mm). In this study, 2195-T8 Al alloy plates with a thickness of 6 mm were subjected to FSW under different welding speeds of 200–800 mm/min with the objective of seeking an optimised welding parameter. The tensile strength of ∼422 MPa at a relatively high welding speed of 400 mm/min with a tool rotational speed of 800 rpm was obtained, which reached a comparable level to those of the joints with low welding speeds. The combination of moderate tool rotational speed and moderate welding speed was a feasible optimising direction for FSW of Al–Li alloy with medium thickness.