1. General

1.1 History

In 1920, Rosenham, Haughton and Bingham were the first to demonstrate superplastic behavior by deforming a ternary zinc-aluminum-copper alloy. In 1928, Jenkins achieved 400% tensile elongation with cadmium-zinc and lead-tin alloys heated to a high temperature (0.8 times the melting temperature in Kelvin). By this time, it had already been noted that these deformations were associated with the delayed development of striction in the material. A record was set in 1934 by Pearson in Great Britain, who succeeded in elongating the eutectic bismuth-tin alloy by almost 2,000%. In addition, Pearson demonstrated through metallographic observations that grain size and shape did not appear to change during deformation.

It was not until 1946 that the superplastic...