The rotary friction welding technology was used to weld 1Cr18Ni9Ti stainless steel (SS) to Al6061

the weld formation

microstructure and mechanical properties of the joints of SS-aluminum under different process parameters were analyzed. The results show that the element diffusion occurred at the interface between stainless steel and aluminum alloy. A bonding layer with certain thickness was found

which became thicker with the increasement of the rotation speed. With the increasement of the upsetting force

the thickness of the bonding layer first increased and then decreased. The aluminum alloy grains at the interface of steel and aluminum are elongated and deformed

and the grain is refined

the hardness near the joint interface is relatively high. The tensile strength of the joint first increased and then decreased with the increase of the rotation speed and upset force

reaching 262 MPa when the rotation speed is 600 r/min and the upset force is 3.8 kN. The fracture location is mainly at the steel-aluminum connection interface

and partly at the aluminum alloy side

there are small and shallow dimples on the weld fracture.