Tribological behaviour of recursive friction stir processed AA7075

Purpose This study aims to investigate and present the tribological behaviour of recursively friction stir processed 7075 aluminium alloy. Design/methodology/approach In this work, aluminium 7075 alloy is friction stir processed recursively by varying the tool rotational speed, traverse speed and the number of passes. Wear pins for testing were extracted from the processed zone and the surfaces were prepared. Wear tests were conducted as per the standard on a pin-on-disc wear testing machine at constant testing conditions and the corresponding tribological properties were analysed. The worn surface and the debris were analysed using a field-emission scanning electron microscope with energy dispersive spectroscopy analysis and elemental mapping to identify the mode of wear mechanism. Findings The experimental results indicate that the specimen fabricated at 1,150 rpm of tool rotation speed and 60 mm/min of traverse speed with 4 passes had the highest wear resistance and the minimum friction coefficient. Originality/value This paper details the effect of recursive friction stir processing on the surface of AA 7075 to improve the tribological properties. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2020-0070/