In-situ Heating-Stage EBSD Validation of Algorithms for Prior Austenite Grain Reconstruction in Steel

Prior-austenite grain (PAG) structures play a critical role in determining steel microstructures and properties. Over recent years, the use of algorithms that reconstruct PAGs from electron backscatter diffraction (EBSD) measurements of martensitic or bainitic microstructures have become commonplace. These appear to work well, but there has yet to be a comparison made of the reconstructed PAG microstructure to the true PAG microstructure of a steel measured above Ae3 before transformation. Here, in-situ EBSD was used to record the austenite grain structure (at 1000 ˚C) before transformation, as well as the progress of subsequent martensitic and bainitic transformations. The resulting dataset, which we have made available to the community here: https://doi.org/10.5281/zenodo.8348372, was used to assess of two popular algorithms for PAG reconstruction. They were found to be accurate enough for PAG size measurement and general texture analysis, although the exact morphologies of some PAG and twin boundaries are sometimes lost.