Pushing electron microscopy to directly image quadrupolar strain fields at shear bands in metallic glasses
The techniques of scanning transmission electron microscopy (S/TEM) are central to the study of shear bands in metallic glasses. Recent research by scientists at KIT from the Helmholtz Research Field Information using 4D-STEM and Machine Learning now provides new insights into the formation of shear bands on the nanometer scale.
For decades, scanning transmission electron microscopy (S/TEM) techniques have been used to analyze shear bands in metallic glasses and understand their origins, with the aim of improving the mechanical properties of metallic glasses. However, due to the lack of direct information in reciprocal space, conventional S/TEM cannot characterize the local strain and atomic structure of amorphous materials, which are crucial for describing the deformation of glasses. Now, 4D-STEM has been employed at KIT to simultaneously image and directly correlate the local strain and atomic structure on the nanometer scale in deformed metallic glasses. For the analysis of large 4D-STEM datasets, machine learning (ML) approaches were used to for the first time map and characterize Eshelby quadrupoles that arise during shear band formation in metallic glasses. Strain fields were observed that percolate in a vortex-like manner and construct the shear band. This provides an entirely new understanding of the formation of shear bands in metallic glasses.
The original publication can be found at (Open Access):
Kang, S.J., Wang, D., Caron, A., Minnert, C., Durst, K., Kübel, C., Mu, X. (2023): Direct Observation of Quadrupolar Strain Fields forming a Shear Band in Metallic Glasses, Advanced Materials 35 (25), 2212086. http://doi.org/10.1002/adma.202212086
Localization in the Helmholtz Research Field Information:
Helmholtz Research Field Information, Program 3: Materials Systems Engineering Processing, Topic 5: Materials Information Discovery
Contact:
Prof. Dr. Christian Kübel
Institute of Nanotechnology
Research Unit: Advanced Electron Microscopy in Materials Research
Karlsruhe Institute of Technology (KIT)
Phone: +49 2461/61-28970
E-Mail: christian.kuebel@kit.edu
Dr. Xiaoke Mu
Institute of Nanotechnology
Research Unit: Advanced Electron Microscopy in Materials Research
Karlsruhe Institute of Technology (KIT)
E-Mail: xiaoke.mu@partner.kit.edu
