An alloy of aluminum containing magnesium, silicon and optionally copper in amounts in percent by weight falling within one of the following ranges:(1) 0.4.ltoreq.Mg.ltoreq.0.8, 0.2.ltoreq.Si.ltoreq.0.5, 0.3.ltoreq.Cu.ltoreq.3.5;(2) 0.8.ltoreq.Mg.ltoreq.1.4, 0.2.ltoreq.Si.ltoreq.0.5, Cu.ltoreq.2.5; and(3) 0.4.ltoreq.Mg.ltoreq.1.0, 0.2.ltoreq.Si.ltoreq.1.4, Cu.ltoreq.2.0; said alloyhaving been formed into a sheet having properties suitable for automotive applications. The alloy may also contain at least one additional element selected from the group consisting of Fe in an amount of 0.4 percent by weight or less, Mn in an amount of 0.4 percent by weight or less, Zn in an amount of 0.3 percent by weight or less and a small amount of at least one other element, such as Cr, Ti, Zr and V. The alloy may be fabricated into sheet material suitable for automotive panels by, in a belt casting machine, producing alloy sheet by casting the alloy while extracting heat from the alloy at a rate that avoids both shell distortion of the sheet and excessive surface segregation, at least until said alloy freezes; solution heat treating the sheet to re-dissolve precipitated particles; and cooling the sheet at a rate that produces a T4 temper and a potential T8X temper suitable for automotive panels. By such means, panels suitable for automotive use can be produced efficiently and economically.