Scandium addition significantly alters the corrosion resistance and mechanical strength of Al-3 Mg alloys. The addition of 0.3% - 0.4% scandium with 0.14% zirconium has a beneficial effect on the corrosion resistance of the alloy under smoothly stirred condition. Addition of 0.3% Sc significantly suppresses corrosion under dynamic flow conditions. It also creates an optimal strengthening effect on the alloys. The corrosion resistance is attributed to the strong passive layer of Sc2O3 formed on the ultrafine coherent precipitates of Al3Sc. A strong evidence of the pinning of grain bounda-ries by coherent nano Al3Sc precipitates is responsible for the strengthening effect.
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