To obtain fine-grained sheet materials, 5083 aluminum alloy (Al-4.5Mg-0.7Mn-0.1Cr) was severely rolled at elevated temperatures (100-400 deg C). The rolling was performed in only one pass, and the reduction ratio was varied from 50 to 88 percent. The grain sizes were reduced to less than 3 microns in the surface region. For samples rolled at a temperature of less than 300 deg C and a reduction ratio of more than 70 percent, the grains in the middle region were about 8-10 microns. It is important that a large shear deformation was added from the surface to the middle region. It was necessary to adjust the temperature of the rolled sheets to about 350 deg C in order to form a fine recrystallized structure in all regions. The yield stress and elongation of a commercial 5083 alloy are 140 MPa and 23 percent, respectively, but they were improved to 190 MPa and 24 percent by the previous processes.
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