Characterization of 6061-T6 aluminum alloy to AISI 1018 steel interfaces during joining and thermo-mechanical conditioning

Friction welds between 6061-T6 aluminum alloy and AISI 1018 steel have been examined in the as process condition and following thermo-mechanical treatment. Joints were characterized by microhardness mapping, focused ion beam with ultra high resolution scanning electron microscopy and transmission electron microscopy with energy dispersive spectrum. Intermetallic layer thicknesses at the interfaces ranged from 250 to 400 nm. These intermetallics appear related to the FeAl and Fe2Al5 phases for as-welded condition and FeAl, Fe2Al5, FeAl3 and FeAl6 phases following thermo-mechanical condition.