In this paper, the microstructural changes associated with phase transformation and the straining behavior in polycrystalline structures during transformation superplastic deformation are investigated. In-situ observations of microstructural changes during Ac//3 transformation on rapid heating in pure iron have been carried out with a high temperature optical microscope and a dark field reflection high temperature microscope. Both microscopes were specially designed for this study. The distribution of superplastic strain has been examined by microscopic strain analyses using a micro-grid pattern with 12. 7 mu m intervals. The observations suggest that sliding at the migrating transformation interface is a principal mechanism of transformation superplasticity.
|Number of pages||9|
|Journal||Transactions of the Iron and Steel Institute of Japan|
|Publication status||Published - 1987|
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