Microstructure, mechanical, and force-torque generation properties of friction stir welded third generation Al/Li alloy at higher traverse speed

The third generation of aluminium lithium alloys has been used primarily in aircraft and spacecraft structures for customized facilities to reduce weight and improve performance. Therefore, the present study has investigated the implication of varying tool rotation speed (TRS) from 700 rpm to 1600 rpm on the force, torque, heat generation, microstructure, and mechanical strength of friction stir welded 2050-T34 Al-Cu-Li alloy plates at a constant higher traverse speed (10 mms⁻¹) and tool tilt angles of 2°. The experimental results reveal that increasing TRS decreases the weldment surface's force, torque, ripple space, and grain size. However, the heat input increases during friction stir welding with increasing TRS. The joint efficiency (87.9 %) and tensile strength (343.5 MPa) are obtained maximum at higher TRS(1600 rpm). Further, mixed and ductile failure modes are observed at the lower and higher TRS, respectively.