Microstructural Variation and Corrosion Behavior of 60/40 Brass/Ti₂SC Surface Composite through Friction Stir Processing

In this paper, the Ti₂SC MAX phase was used as a reinforcement to produce 60/40 brass surface composites using friction stir processing (FSP). The effect of FSP and Ti₂SC MAX phase reinforcement particles on the electrochemical behavior of the brass alloy and its surface composite was studied in NaCl solution (3.5 wt.%). Microstructural features of the specimens were assessed by optical microscopy and scanning electron microscopy equipped with energy-dispersive spectroscopy. Also, the corrosion behavior of the base metal and FSPed samples with and without Ti₂SC particles was examined by different electrochemical methods such as cyclic polarization, potentiodynamic polarization, and electrochemical impedance spectroscopy. The FSP caused grain refinement and homogeneous distribution of Ti₂SC particles in the brass matrix. The results revealed that the presence of reinforcement particles and the number of FSP passes had considerable effects on the corrosion resistance of the specimens. For FSPed samples with or without reinforcement particles, corrosion resistance decreased by increasing the pass number from 1 to 3. The corrosion current density of brass alloy was 12.5 µA.cm⁻², while this value exceeded 30 µA.cm⁻² for all FSPed samples after FSP.