Abstract
Failure during superplastic deformation (SPD) may result from geometrical macroscopic instabilities and/or microstructural aspects. However, the available failure criteria are based either on geometrical instabilities or microstructural features and do not account for both failure modes. In this work, a new multiscale stability criterion is developed by combining a modified microstructure-based constitutive equation with grain and cavitation evolution equations. The new criterion is used to design optimum variable strain rate forming paths for Ti-6Al-4V SP alloy. The effects of void fraction, grain size and strain rate sensitivity on the optimum forming paths are also examined. In addition, FE analysis of superplastic blow forming of a hemisphere is carried out using the optimum forming path and the results are compared with those obtained using constant strain rate forming paths. It is shown that the proposed multi-scale criterion can reduce the forming time without causing localized deformation and thinning.
Original language | English |
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Pages (from-to) | 105-110 |
Number of pages | 6 |
Journal | Materials Science Forum |
Volume | 447-448 |
DOIs | |
Publication status | Published - 2004 |
Externally published | Yes |
Event | Superplasticity in Advanced Materials: 8th International Conference on Superplasticity in Advanced Materials, ICSAM 2003 - Oxford, United Kingdom Duration: 28 Jul 2003 → 30 Jul 2003 |
Keywords
- Finite Element Simulation
- Microstructural Evolution
- Optimum Forming
- Stability Analysis
- Superplastic Deformation