Integrierter Ansatz zur lokalen, electron channeling basierten Spannungs- und Dehnungsmessung im Rasterelektronenmikroskop (εpsilator.X3)
Zusammenfassung der Projektergebnisse
In this project, methods of High-Resolution Electron Backscatter Diffraction (HR-EBSD) were adapted to the analysis of Selected Area Channeling Patterns (SACP). The aim was to utilize the significantly higher angular resolution and better quality of SAC patterns compared to EBSD in order to achieve a higher strain resolution; ideally using dynamically simulated reference patterns to determine the absolute strain. For this purpose, an Integrated Digital Image Correlation model (IDIC) was developed, which specializes in the matching of simulated with real SACP. It integrates a partial model for correcting the sometimes considerable lens distortion, as well as one for correcting the fluctuating brightness conditions due to the inclination of the surface or the detector characteristics. As usual, the model was validated using virtual experiments. Finally, a sample was elastically deformed in situ in the SEM to record experimental SACP with a known deformation state. The practical suitability of the model was tested on these. The sensitivity of the method to elastic distortion was demonstrated, but even after the system had drifted out over many hours, the influence of beam drift was considerable. This led to significant, time-dependent phantom distortions in the evaluation. Unfortunately, several approaches to correction were unable to produce satisfactory results.
