Fabrication of Al5083/TiO2 surface composite by friction stir processing and investigation of microstructural, mechanical and wear properties

The fabrication of nano‐composites is quite challenging because uniform dispersion of nano‐sized reinforcements in metallic substrate is difficult to achieve using powder metallurgy or liquid processing methods. Friction stir processing (FSP) is a new solid-state process used to modify the refinement of microstructure, improvement of material’s mechanical properties and production of surface layer composites. In this investigation via friction stir processing, metal matrix composite surface (MMCs) was fabricated on surface of 5083 aluminum sheets by means of 5 μm and 80 nm TiO2 particles. The friction processed surface composite layer was analyzed throughoptical and scanning electron microscopical studies. Effects of reinforcing particle size and FSP pass number on the microstructure, microhardness, on tensile and wear properties of the developed surfaces were investigated. Results show that the created nanocomposite layer by TiO2 particles exhibits a microstructure with smaller grains and higher hardness, strength, and elongation compared to the composite TiO2 layer by particles. Increasing FSP pass number results in improved distribution of particles, finer grains, and higher hardness, strength, elongation, and wear resistance. The surface composite layer resulted in four passes with change in rotation direction with nano particle reinforcement exhibited better properties in hardness, tensile behavior and wear resistance compared tothe behavior of the base metal.