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Free keywords:
Austenite; Diffraction patterns; Electron diffraction; Interferometry; Phase comparators; Template matching, Body-centered cubic; Face-centered cubic; Nano-sized precipitates; Nanobeam electron diffraction; Orientation relationship; Phase precipitate; Pixelated detectors; Two stage template matching, Crystal orientation
Abstract:
Scanning nano-beam electron diffraction with a pixelated detector was employed to investigate the orientation relationship of nanometer sized, irradiation induced G-phase (M6Ni16Si7) precipitates in an austenite matrix. Using this detector, the faint diffraction spots originating from the small G-phase particles could be resolved simultaneously as the intense matrix reflections. The diffraction patterns were analyzed using a two-stage template matching scheme, whereby the matrix is indexed first and the precipitates are indexed second after subtraction of the matrix contribution to the diffraction patterns. The results show that G-phase forms with orientation relationships relative to austenite that are characteristic of face-centered cubic (FCC) to body-centered cubic (BCC) transformations. This work demonstrates that nano-beam electron diffraction with a pixelated detector is a promising technique to investigate orientation relationships of nano-sized precipitates with complex crystal structures in other material systems with relative ease. © 2021 The Author(s)
