Optimized EBSD-TEM method for the investigation of Al/Al2O3 interfacial orientation mismatch

Abstract

The combined electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) method has been commonly applied to investigate material interfaces, from the perspectives of orientation and atomic structure. However, the loose combination is inadequate to capture some slight deviation from the ideal mismatch of interface, which limits an in-depth understanding of the interface. In this study, the combined EBSD-TEM method was systematically optimized and applied to investigate Al-Al2O3 heterogeneous nucleation interface. In this optimized EBSD-TEM method, the cylindrical equidistant projection was employed to illustrate the orientation mismatch relationship instead of the widely used pole figure. Lattice planes and directions from two phases are systematically presented in one figure, which provides a thorough perspective to identify all the potential matching features within the interface, meanwhile ensures a precise guidance for TEM sampling and observation. Such guidance is crucial for interface investigations, thereby this optimized EBSD-TEM method has great potential to be widely applied. Complex interface configurations of Al-Al2O3 interfaces were revealed, including the tilting of Al phase low-indexed planes relative to the interface and the deviations of matched lattice direction pairs between two phases. The complex interface configurations urge further development in the theory of nucleation interface mismatch.