Restitution of the Shapes and Orientations of the Prior Austenitic Grains from Inherited Alpha' Orientation Maps in Steels
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.
Yves Bréchet, Emmanuel Clouet, Alexis Deschamps, Alphonse Finel and Frédéric Soisson
N. Gey et al., "Restitution of the Shapes and Orientations of the Prior Austenitic Grains from Inherited Alpha' Orientation Maps in Steels", Solid State Phenomena, Vols. 172-174, pp. 911-915, 2011