Recrystallization of twin-roll cast Al-Fe-Si foil stock processed without homogenization

Differential scanning calorimetry, hardness testing, electrical conductivity measurements and microstructural analysis were employed in the present work to investigate the response of twin-roll cast Al-0.8Fe-0.6Si strips to interannealing without prior homogenization. Recrystallization which occurs at 400 degrees C in sheet samples cold rolled only lightly (epsilon similar to 0.2) is gradually displaced to lower temperatures with increasing strain until epsilon similar to 2.3. Precipitation occurs largely before a measurable recrystallization reaction at low strains, epsilon < 2.3, producing an acceptable grain structure across the section. The interaction of the two reactions at epsilon > 2.3 is believed to be responsible for a decreasing recrystallized fraction and for coarse grains at the surface where the interaction is likely to be most pronounced. Interannealing of the Al-0.8Fe-0.6Si alloy without a homogenization treatment produces acceptable grain structures across the section of the strip for much of the cold rolling strain range. It is thus concluded that Al-0.8Fe-0.6Si foil stock, intended for cosmetic foil applications where formability is not critical, could be processed without a high-temperature annealing treatment. (C) 2009 Elsevier B.V. All rights reserved.