ALUMINIUM-MAGNESIUM-SILICON ALLOY AND METHOD OF FORMING EXTRUSION INGOT

摘要

An extrusion ingot of an Al-Mg-Si alloy, has substantially all the Mg present in the form of particles having an average diameter of at least 0.1 microns of beta'-phase Mg2Si in the substantial absence of beta-phase Mg2Si. The ingot may be made by casting an ingot of the alloy, homogenising the ingot, cooling the homogenised ingot to a holding temperature of 250 DEG C. to 425 DEG C. at a cooling rate of at least 400 DEG C./h, holding the ingot for 0.25 to 3 hours, and cooling. The ingot has improved extrusion properties.