A complex part composed of rapidly solidified magnesium base metal alloy is
produced by superplastic forming at a temperature ranging from 160.degree.
C. to 275.degree. C. and at a rate ranging from 0.00021 m/sec to 0.00001
mm/sec, to improve the formability thereof and allow forming to be
conducted at lower temperature. The rapidly solidified magnesium based
alloy has a composition consisting essentially of the formula Mg.sub.bal
Al.sub.a Zn.sub.b X.sub.c, wherein X is at least one element selected from
the group consisting of manganese, cerium, neodymium, praseodymium and
yttrium, "a" ranges from 0 to about 15 atom percent, "b" ranges from 0 to
about 4 atom percent and "c" ranges from about 0.2 to 3 atom percent, the
balance being magnesium and incidental impurities, with the proviso that
the sum of aluminum and zinc present ranges from about 2 to 15 atom
percent. Such an alloy contains fine grain size and finely dispersed
magnesium-, aluminum- rare earth intermetallic phases. When formed, the
part exhibits good corrosion resistance together with high ultimate
tensile strength and good ductility at room temperature, which properties
are, in combination, far superior to those of conventional magnesium
alloys. The part is suitable for application as a structural member in
helicopters, missiles and air frames where good corrosion resistance in
combination with high strength and ductility is important.
