Atomic-Scale Insights into Yttrium-Induced Grain Boundary Structure Modification in Al₂O₃

Area of Science:

• Materials Science
• Nanotechnology
• Solid-State Physics

Background:

• Impurity segregation at grain boundaries (GBs) significantly impacts material properties.
• Understanding atomic-scale mechanisms of GB segregation is crucial for materials design.

Purpose of the Study:

• To investigate the atomic structure of Yttrium (Y)-segregated GBs in alpha-Al2O3.
• To elucidate the mechanism of GB structural transformation induced by impurity segregation.

Main Methods:

• Scanning Transmission Electron Microscopy (STEM).
• Monte Carlo (MC) and Molecular Dynamics (MD) simulations.
• Neural Network (NN) potential for simulations.

Main Results:

• Yttrium segregation involves substitution of Y for Al atoms.
• Segregation induces structural adaptation with altered GB atomic density.
• Changes in bonding environment minimize excess volume, leading to the lowest-energy structure.

Conclusions:

• Yttrium segregation drives atomic-level structural transformations at GBs.
• The study provides new insights into the atomic-scale mechanisms of GB structural changes.
• Findings are critical for controlling material properties through GB engineering.