Strain-Mediated Defect Engineering toward Rapid Atomic Migration in Fe-Al Diffusion Couples.

Area of Science:

• Materials Science
• Physical Chemistry
• Computational Materials Science

Background:

• Rapid atomic migration is crucial for processing lightweight Fe-Al diffusion couples.
• Designing effective short-circuit diffusion paths is essential for controlling diffusion rates.
• Understanding diffusion mechanisms at interfaces and defects is key to material optimization.

Purpose of the Study:

• To propose a strain-mediated defect engineering strategy for enhancing atomic migration in Fe-Al diffusion couples.
• To reduce the vacancy activation energy and improve diffusion along dislocations (DLs) and grain boundaries (GBs).
• To investigate the underlying mechanisms of strain effects on diffusion barriers using first-principles calculations.

Main Methods:

• Strain-mediated defect engineering was applied to Fe-Al diffusion couples.
• Modified Arrhenius-type relationship was used to determine interfacial apparent activation energy.
• First-principles calculations were employed to analyze diffusion barriers and electronic structure changes.

Main Results:

• Defect engineering reduced the interfacial apparent activation energy by approximately 49% to 139 kJ mol⁻¹.
• High densities of vacancies, DLs, and GBs were introduced in strained Fe and Al, providing low-energy diffusion paths.
• First-principles calculations confirmed reduced lattice diffusion barriers due to strain-induced weakening of atom-vacancy bonds and altered electron transport.

Conclusions:

• Strain-mediated defect engineering effectively enhances atomic migration in Fe-Al diffusion couples.
• The synergistic effects of abnormal electron-charge distribution and interfacial attraction promote rapid atomic migration.
• This strategy offers a pathway for controlling diffusion kinetics and optimizing Fe-Al material properties.