A sigmoidal model for superplastic deformation

W. Pan, K. Krohn, S.B. Leen, T.H. Hyde, S. Walloe

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


A new phenomenological model, designed to capture the sigmoidal nature of stress dependency on strain rate for superplastic deformation, is presented. The model is developed for the Ti-6Al-2Sn-4Zr-2Mo alloy using data obtained under controlled strain-rate tensile tests spanning a range of strain rates and temperatures, from 930 to 980 °C. The sigmoidal model performance is compared with that of a more conventional double-power law, strain, and strain-rate hardening model using time-dependent finite element and theoretical analyses. The primary intended application of the sigmoidal model is for more accurate simulation of the effects of strain-rate variation within test specimens and sheet during superplastic deformation. Analysis of this variation within two designs of tensile test specimens is presented to illustrate this aspect.
Original languageEnglish
Pages (from-to)149-162
Number of pages13
JournalProceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications
Issue number3
Publication statusPublished - 2005


  • superplastic deformation
  • sigmoidal model
  • materials design


Dive into the research topics of 'A sigmoidal model for superplastic deformation'. Together they form a unique fingerprint.

Cite this