An Accurate Method for Crystallographic Reconstruction of Parent Austenite from Inherited Martensite in a Low-Alloy Steel

The microstructure of austenite at high temperatures, which cannot be reserved at room temperatures, determines the properties of its transformed phase in low-alloy steels. Consequently, an accurate method is herein developed to reconstruct local orientations of the parent austenite (gamma) phase from electron backscatter di ff raction maps of the martensite (alpha') microstructure. The orientation map of ff 0 is cropped into a grid of data squares as the reconstruction unit. The cropped square is then divided into the square inherited from only one gamma grain and the square inherited from more than one alpha' grain. The local orientations around parent gamma grain boundaries are more accurately determined using a newly proposed reconstruction criterion. Furthermore, the solution spaces for the orientation relationship and the parent gamma orientation are refined, which simultaneously improves the calculation accuracy and efficiency of reconstruction procedure. The validated reconstruction method is applied to obtain local orientations of the deformed gamma microstructure accurately.