On the structure of grain/interphase boundaries and interfaces

Area of Science:

• Materials Science
• Solid State Physics
• Physical Chemistry

Background:

• Material interfaces, including grain and interphase boundaries, exhibit diverse characteristics like misorientation, curvature, and free volume.
• A unified descriptive framework for these interfaces across crystalline and amorphous materials is lacking.

Purpose of the Study:

• To propose a generalized model for describing material interfaces.
• To establish a central concept for a unified theory of grain/interphase boundaries/interfaces.

Main Methods:

• Conceptual modeling based on structural/basic units.
• Consideration of interatomic (including electronic) interactions, atomic/electronic distribution, and free volume.
• Advocacy for representative volume elements for disordered boundaries.

Main Results:

• A generalized model is proposed, centered on a structural/basic unit dependent on interatomic interactions and material properties.
• For highly disordered boundaries, a representative volume approach using non-crystalline basic units is advocated.
• The model acknowledges the influence of experimental conditions and material composition.

Conclusions:

• A generalized model based on structural units offers a unified approach to describing material interfaces.
• The representative volume concept is crucial for understanding highly disordered boundaries.
• Further research is needed to address unresolved issues in quantitative modeling.