Grain refinement and superplastic forming of an aluminum base alloy

摘要

A rapidly-solidified aluminum alloy powder having a nominal composition of 7% Zn, 2.5% Mg, 2% Cu, 0.3% Zr, and 0.3% Cr is used to make a high forming-rate, superplastic, high-strength aluminum alloy. The powder is outgassed, consolidated, and extruded, thereby developing a wide range of particle size distribution of dispersoids in the process, containing respectively zirconium and chromium dispersoids, as well as age hardening precipitates. The consolidated powder is then rolled to 85% reduction to provide a sheet material which is superplastically formed at a temperature in the range of 450° C. to 490° C. and at a rate between 5×10.sup.-3 to 5×10.sup.-2 per second.