Formability of superplastic aluminum alloy processed by mechanical alloying

The superplastic deformation of mechanically alloyed (MA) Al-Cu-Mg and Al-Cu-Mg-Zn alloy has been observed at high strain rates of 10(0)-10(1) s: which correspond to the speed of a general mechanical press. Very fine and stable grains of sub-micron size are obtained by the mechanical alloying process. The formability, and especially the forgability, of these materials are examined by use of the upsetting test and the spike-forging test. The upsetting limit and the forging limit of these materials on a mechanical press are substantially greater than those on a low-speed hydraulic press, so one of the obstacles with conventional superplastic materials, that superplasticity appears only at very low strain rates, is eliminated. (C) 1997 Elsevier Science S.A.