Effect of processing parameters on fabrication of Al–Mg/Cu composites via friction stir processing

Nowadays, fabrication of metal matrix composites (MMCs) with high mechanical properties and modified microstructures has attracted many attentions. One of the methods to produce MMCs is friction stir processing (FSP) which is a novel modifying technique. In this investigation, production of AA5083 aluminum alloy with reinforced layers using copper particles via FSP was discussed. Microstructural characterization was performed through optical microscopy (OM) and scanning electron microscopy (SEM). Effects of rotational speed, FSP pass numbers and Cu particles’ size were investigated on microstructure, particles distribution pattern and microhardness. Results showed that the specimens with micro and nano-sized particles present fine grains and higher level of hardness. Tensile properties of specimens friction stir processed with and without Cu particles were also evaluated. According to the results, the composite with nano-sized particles exhibited enhanced tensile strength and ductility rather than AA5083 aluminum alloy. X-ray diffraction (XRD) studies were carried out on the specimens FSPed with Cu particles in order to identify the phases present in the stir zone (SZ) of the specimens.

► Al5083/Cu surface composite layer was successfully fabricated via FSP.
► Addition of Cu particles improves the grain size.
► Composites with nano-sized Cu particles show higher UTS and hardness values.
► XRD observations show some reactions between the alloying elements.