This work focuses on the effect of annealing, normalizing and tempering on corrosion behavior of Al-4Ti/1 wt% MgO-2 wt% SiC composite fabricated by stir casting method. The XRD analysis and optical examination indicate that the heat treatments lead to breaking up the main phase (Al3Ti) in Al-4Ti alloy and form many oxides that cover the composite surface.
Linear and cyclic polarizations have been investigated in seawater at room temperature by Potentiostat. The corrosion data showed that the corrosion potential became more negative for heat treated composites compared with untreated once. Corrosion current density decreased after heat treatments. The normalized composite has lowest corrosion rate due to expose the specimen to atmosphere for quenching which leads to form SiO2 in addition to MgO and Al2O3. The breakdown of passive layer in composite decreased by heat treatments which assessed by cyclic polarization test.