Wear characteristics of Al–Cr–O surface nano-composite layer fabricated on Al6061 plate by friction stir processing

Al–Cr–O hybrid nano-composites have been fabricated in-situ on the surface of Al6061 plate by friction stir processing (FSP) and their wear resistance has been investigated and compared with Al6061-T6 and friction stir processed (FSPed) Al6061-T6. A new procedure was introduced for applying the reinforcement particles, in which Cr2O3 powder was applied on Al6061 plate by atmosphere plasma spray and then the FSP was performed on the plate. During FSP due to thermomechanical condition, Cr2O3 was reduced with aluminum so pure Cr and Al2O3 were produced and as a result of reaction between Al and Cr, intermetallic compounds including Al13Cr2 and Al11Cr2 appeared. Dry sliding wear tests were applied using a reciprocating wear test. Results showed improved wear resistance in nano-composite samples. Al6061-T6 plate after FSP showed lower wear resistance than Al6061-T6 and nano-composites. This is due to the loss of hardening precipitates as a result of FSP. •Performing FSP on Al that is coated with Cr2O3 results in fabrication of Al–Cr–O nano-composite.•FSP reduced the wear resistance of Al6061-T6 due to the loss of precipitates.•The wear mechanism for nano-composite was different from Al6061and FSPed samples.•Reinforcements act as hard ceramic phase in Al and improve the wear resistance.