Developing High Strain Rate Superplasticity in Aluminum Alloys
The conventional materials used in superplastic forming operations generally have grain sizes of ~2 µm or larger and they exhibit superplasticity at relatively low strain rates. Processing by equal-channel angular pressing (ECAP) produces materials having ultrafine-grain sizes, usually in the submicrometer range. If these ultrafine grains show reasonable stability at elevated temperatures, the alloys may exhibit a capability for achieving superplastic elongations at high strain rates. This paper examines the development of ultrafine-grained structures and superplastic ductilities in a spray-cast aluminum 7034 alloys through ECAP. The results show that ECAP is a very effective procedure for achieving grain refinement and superplasticity at rapid strain rates.
Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie
C. Xu et al., "Developing High Strain Rate Superplasticity in Aluminum Alloys", Materials Science Forum, Vols. 475-479, pp. 2949-2954, 2005