Effect of accelerating voltages on indexing of SEM-EBSD via pattern matching

The influence of the accelerating voltage on the spatial resolution and phase indexing accuracy of electron backscattered diffraction (SEM-EBSD) was systematically investigated using austenitic heat-resistant steel. Both traditional Hough transformation and novel Spherical Indexing methods were employed to analyze the kernel average misorientation (KAM) and indexing of fine M₂₃C₆ precipitates. It was confirmed that lower accelerating voltages reduce the interaction volume, thereby improving the spatial resolution. Spherical Indexing provided enhanced accuracy in detecting local misorientations, especially in the creep-ruptured material. While the effect of the accelerating voltage on KAM was minimal, it became significant when indexing fine precipitates. At 10 kV, precipitates as small as 50 nm on the Σ3 boundaries could be indexed, whereas precipitates of 200 nm at 15 kV and 300 nm at 25 kV were required for reliable identification. These results demonstrate the critical role of measurement conditions in advanced EBSD microstructural characterization and suggest the effectiveness of Spherical Indexing for high-resolution evaluation of creep damage and phase separation of nanoscale features.