Improving the tribological characteristics of aluminum 6061 alloy by surface compositing with sub-micro-size ceramic particles via friction stir processing

► A thick (>1 mm) composite surface layer with >20 vol.% of sub-micro-size ceramic particles was formed by using friction stir processing on an Al 6061-T6511 alloy. ► The composite surface demonstrated promising mechanical and tribological properties. Specifically, the introduction of sub-micro-size particles reduced friction by 40% and enhanced the wear-resistance by one order of magnitude. ► Characterization revealed increased dislocation density in the aluminum matrix of the composite corresponding to the enhanced mechanical and tribological properties.