Restitution of the Shapes and Orientations of the Prior Austenitic Grains from Inherited Alpha' Orientation Maps in Steels

Abstract:

We propose to reconstruct the g orientation maps from the α maps inherited by the bainitic or martensitic γ→α phase transformation. Our approach comprises two main steps (1) identification of reliable fractions of parent grains – each γ fraction is determined from neighbouring variants related to a unique γ orientation with a low tolerance angle; (2) expansion of these fractions by collecting adjacent variants being in orientation relation (OR) with the calculated g orientation - using a higher tolerance around the strict OR. Moreover, this fully automated g map reconstruction is further improved by an additional semi-automated analysis of α/γ maps. This reconstruction procedure was applied to the α microtexture of bainitic steels. The reliability of the calculations was checked by comparing each γ grain orientation and their corresponding α variants. The results show that even with a large spread around OR, the shape and orientation of most of the γ grains are accurately calculated.

• Periodical: Solid State Phenomena (Volumes 172-174)
• Pages: 911-915
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.172-174.911
• Online since: June 2011
• Authors: Nathalie Gey, Pierre Blaineau, Lionel Germain, Michel Humbert, David Barbier, Astrid Perlade
• Keywords: Austenite, Crystallographic Reconstruction, Electron Backscatter Diffraction (EBSD), Martensite, Phase Transformation

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