A PROCESS FOR THE PREPARATION OF ALUMINIUM-ZINC-MAGNESIUM-MANGANESE-ZIRCONIUM-SCANDIUM ALLOY

摘要

A process for the preparation of Aluminium-Zinc-Magnesium-Mangenese-Zirconium-Scandium alloy comprising the steps of; preparing a charge mixture of primary aluminium and Al-8.5wt % Mn master alloy; melting at 720 to 730°C the said charge mixture, adding to this molten charge elemental pure Zn followed by raising the temperature of the molten charge as herein described; adding of Al-50wt% Mg master alloy, Mg-28wt% Zr master alloy and Al-2wt% Sc master alloy in the above sequential order to the molten charge followed by super heating for a period of 10 minutes; adding nuclent pellets as herein described at reduced temperature of 735-745°C for grain refinement; degassing the molten melt to remove dissolved gases and pouring the molten melt under indert gas atmosphere, preferably argon atmosphere, into a pre-heated mould; homogenizing, scalping and rolling the sound billets into plates; solution treating, quenching, and stretching the alloy sheets followed by two-step artificial aging.