Phase decomposition in Al-6Mg alloy castings containing minor addition of scandium and zirconium

摘要

The effect of trace scandium and zirconium addition on the phase decomposition behavior of aluminium magnesium alloy is studied with AI-6Mg alloys containing various amount of trace addition. Transmission electron microscopy has revealed that the properties of cast alloys after annealing are decided by the morphology and character of the precipitates. It is further demonstrated that the improvement in fracture toughness achieved by the addition of zirconium in Al-6Mg-0.4Sc alloy is due to the reduction of the in-plane anisotropy which is secured by a favorable precipitate morphology.