High Strength Wrought Aluminium Alloys from the Casting Heat

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The aim of the project is to research the material science relationships between manufacturing parameters, microstructures and properties for a novel process chain for the production of extruded high-strength wrought aluminium alloys. This novel process chain should lead to a considerable reduction in the necessary energy input through the continuous use of the casting heat. The multiple cooling and reheating between the high process temperatures of casting, homogenisation annealing, hot forming and solution annealing shall be saved. The working hypothesis is that high-strength wrought aluminium alloys can be produced from the casting heat through the purposeful selection of alloys and process parameters if homogenisation, hot forming and solution annealing are carried out in a temperature range justified by phase diagrams, i.e. below the solvus temperature of dispersoid-forming alloying elements (e.g. Mn, Fe) and above the solvus temperature of precipitation-hardening alloying elements (e.g. Mg, Si). In this process window, dispersoids should already be formed in order to hinder grain growth, but the precipitation-hardening alloying elements should still remain dissolved in order to set a high ageing potential after quenching. This seems to be purposeful because the dispersoid-forming alloying elements (e.g. Mn, Fe) usually have lower temperature-specific solubilities in the aluminium solid solution than precipitation-hardening alloying elements (e.g. Mg, Si).