Understanding solute effect on grain boundary strength based on atomic size and electronic interaction

Area of Science:

• Materials Science
• Computational Materials Science
• Physical Metallurgy

Background:

• Solute segregation at grain boundaries can stabilize nanocrystalline material microstructures.
• However, many solutes can also cause embrittlement, negatively impacting interfacial strength.
• Understanding solute effects is crucial for designing robust nanocrystalline alloys.

Purpose of the Study:

• To systematically investigate the influence of various solutes on the strength of a Σ5 (310) grain boundary in copper (Cu).
• To elucidate the relationship between solute properties (atomic radius, electronic interactions) and grain boundary strength.
• To provide insights for the rational design of nanocrystalline alloys with enhanced mechanical properties.

Main Methods:

• Utilized first-principle calculations to simulate and analyze solute interactions at copper grain boundaries.
• Examined the correlation between solute atomic radius and grain boundary embrittlement.
• Investigated the role of electronic interactions, particularly d-state interactions in transition metals, on grain boundary strength.

Main Results:

• Solute effects on grain boundary strength are governed by atomic radius and electronic interactions with copper.
• Larger atomic radius solutes segregate readily but increase embrittlement.
• Transition metallic solutes with strong d-state interactions significantly enhance grain boundary strength, counteracting size mismatch effects.

Conclusions:

• The study reveals that transition metallic solutes are promising for improving grain boundary strength in copper-based nanocrystalline materials.
• Electronic interactions, especially d-state interactions, play a critical role in mitigating embrittlement and enhancing strength.
• Findings deepen the understanding of atomic size and electronic effects on grain boundary mechanical properties.