Abstract
In order to evaluate the basic characteristics of superplastic materials, an R-type specimen has been proposed, which has no ordinary gauge part of a uniform cross section.
First, the fundamental problems of a conventional evaluation method have been pointed out. Then, the superplastic characteristics of a Zn-Al eutectoid superplastic alloy have been examined to investigate the possibility of the new evaluation method using the R-type specimen.
As a result, it is found that the R-type specimen has the excellent possibility. In particular, the extremely high elongation can be estimated from a peak value of strain distribution after fracture. Moreover, true stress versus true strain rate relation and m-value in a wide range of strain rate can be derived from the results for a pair of R-type specimens.
