Multi-response Optimisation Applied on Friction Stir Processing to Enhanced Wear and Corrosion performance in Al-Si Alloys

Abstract Eutectic (Al12Si) and hyper-eutectic (Al14Si) Al–Si alloys were processed through friction-stir processing (FSP). These Al-Si alloys' microstructure, microhardness, wear, and corrosion behaviour were studied. FSP led to the fragmentation and uniform distribution of Si and Fe-rich intermetallic phases in the Al matrix. Multi-response optimisation of the friction-stir process of Al–Si alloys was investigated. The optimum FSP parameters were a tool rotation speed of 1100 rpm and a 16 mm/min travel speed for Al12Si alloy. The friction stir processed Al12Si samples exhibit the highest microhardness (93 Hv); the most considerable fragmentation of Si particles and Fe-rich intermetallic phases, with average sizes of 2.82 and 2.07 µm, respectively; and optimal values of coefficient of friction (0.60); and corrosion rate (1.28×10⁻ ⁴ mm/y). This work provided a mathematical model to obtain the optimum FSP parameters for producing surfaces in Al12Si alloys with excellent microstructural characteristics, high hardness, and better wear and corrosion resistance.