Evaluation of Interface Microstructure and Bonding Strength for Dissimilar Rotary Friction Welding of E46 and AA6061-T6

Nowadays, friction welding is recognised as a highly productive and economic joining process for similar as well as dissimilar welding of automobile and aerospace components. Friction welding is the viable solution to offset the challenges of dissimilar fusion welding due to varying thermal and physical properties as well as limited mutual solubility. This study investigated interface microstructure and bonding strength of dissimilar rotary friction welding of 3.15 mm E46 plate and 45 mm AA6061-T6 rod. The direct drive rotary friction welding of E46 and AA6061-T6 is performed at combinations of two different friction times (4 sec and 7 sec) and forging pressure (108 MPa and 125 MPa). Mechanical bonding strength at the interface is evaluated based on the push-off and multistep shear tests. Further, a fractured steel surface was visually examined to understand the failure mechanism of welded joints. The microstructure of friction welded joint is divided into three regions: dynamic recrystallisation region, thermos-mechanically affected zone and base metal. The maximum average push-off strength of 132.40 MPa and shear strength of 115.50 MPa were obtained at 4 sec friction time and 125 MPa forging pressure.