Revisiting Crystalline Orientation Relationship Measurements via Electron Diffraction - Enhancing Efficiency and Accuracy through Post‑Processing

Crystalline orientation relationships (OR) between adjacent grains or phases are essential for characterize grain boundaries and interfaces in structural and functional crystalline materials. Although electron-diffraction -based methods for OR determination exist, it remains necessary to measure OR individually when established solutions are not applicable or when specimen thickness and Kikuchi line information cannot be reliably obtained. In this study, we revisit the systematic tilting method in transmission electron microscopy (TEM) for grain OR measurement and introduce a post-processing strategy to enhance both angular accuracy and the efficiency. Among the algorithms assessed, least-squares fitting (LS) and singular value decomposition (SVD) algorithms demonstrate superior angular accuracy, whereas the normalization approach provides only marginally acceptable accuracy though convenient for on-site user. The proposed data-processing workflow was validated using two well-known orientation relationships: the [110]/69.5° twin OR in TiAl intermetallic and the Kurdjumov-Sachs OR between austenite and ferrite phases in dual-phase stainless steels.