Fine-grain AA5083 is the most common Al-Mg alloy for Superplastic forming (SPF) of light-weight sheet-metal parts in the automotive and aerospace industries. The fine-grain 5083 aluminum sheet is industrially produced by massive cold rolling of conventionally rolled sheet stock at high cost. Friction Stir Processing (FSP) as a thermomechanical process is very effective in refining the microstructure of as-cast alloys such as produced by continuous strip casting (CC). In this work, the effect of friction stir processing on the superplastic properties of continuous cast 5083 Al plates have been investigated, optimizing the Mn content. Three continuous cast 5083 Al alloy was friction stir processed using several parameters. Ultra-fined microstructures with grain sizes less than 3 μm were obtained. Tensile test revealed that the maximum tensile elongation of 810% was achieved at 530 ºC and 3x10-2 /s in the alloy with the lowest Mn content. The stability of the microstructure at elevated temperature was the most important issue to overcome.
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