An Investigation of Composite Inclusion Corrosion Resistance Behavior of Thermally Liquid-Melt Inoculated Al-Mg-Si Alloy in Sodium Chloride Medium

摘要

Inoculation enhances component performance in corrosive oxidizing environments and this provides appreciated protection in high temperature/stress applications. The corrosion enhancement of Al-Mg-Si alloy in 3.65 % NaCl solution with varying concentrations of titanium composite and minor addition of Sn has been studied using linear potentiodynamic polarization. The mechanical property was examined using the micro-hardness technique. From the results all the alloyed samples exhibited lower decreases in corrosion rate with increases in hardness values as the percent of TiO2 and SnO2 increases up to 10 %wt in the Al-Mg-Si alloy as compared to the as-cast sample. Strengthening efficiencies of 78, 77 and 30 % were obtained at Al/10Ti-Sn, Al/10Ti and Al/5Ti, respectively. The optimum values were obtained at 10 wt%Ti-Sn. The increases in hardness values and corrosion resistance are attributed to the formation of coherent and uniform precipitation in the metallic lattice. These results show that improved corrosion and mechanical properties are achievable by subjecting the cast Al-Mg-Si alloy to inoculation.