ALUMINUM ALLOY SHEET AND METHOD FOR MANUFACTURING SAME

摘要

An aluminum alloy sheet includes an aluminum alloy substrate having a composition containing, by mass percentage, 3.0 to 4.0% of magnesium, 0.2 to 0.4% of manganese, 0.1 to 0.5% of iron, not less than 0.03% but less than 0.10% of copper, and less than 0.20% of silicon, with the remainder being aluminum and unavoidable impurities. A peak concentration of a copper concentration distribution in a thickness direction in a region at a depth of 15 nm to 200 nm from the surface of the aluminum alloy substrate is equal to or more than 0.15%, and the aluminum alloy substrate has a recrystallized structure with an average grain size of 15 µm or less.