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. The main objective of this study is to evaluate the interface microstructure and interface bonding strength for dissimilar rotary friction welding of 3.15 mm E46 disc and 45 mm AA6061-T6 bar at different friction time and forging pressure. The direct drive rotary friction welding of E46 and AA6061-T6 is performed at combinations of two different friction time (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 multi-step shear strength. Further, fractography of failed samples is carried out to understand the failure mechanism of welded joints. Metallurgical investigation shows that friction welding forms a thin diffusion zone of Fe and Al atoms at the interface, which is responsible for a strong metallurgical bond.