Forced chemical mixing in alloys driven by plastic deformation

Area of Science:

• Materials Science
• Computational Materials Science
• Solid State Physics

Background:

• Atomic mixing in alloys is crucial for material properties.
• Plastic deformation can induce atomic rearrangement.
• Understanding mixing mechanisms under stress is key for alloy design.

Purpose of the Study:

• To investigate atomic mixing in crystalline binary alloys during plastic deformation using molecular dynamics.
• To identify factors influencing the extent of atomic mixing.
• To elucidate the mechanisms driving forced atomic mixing.

Main Methods:

• Molecular dynamics simulations at 100 K.
• Analysis of mean square relative displacement (sigma(2)(R,t)).
• Visual inspection of atomic displacement fields.

Main Results:

• Nearly complete atomic mixing observed in systems with large positive heat of mixing or lattice mismatch.
• No mixing occurred in systems with a hard precipitate in a soft matrix.
• Forced mixing is driven by dislocation glide, analogous to turbulent advection.

Conclusions:

• Plastic deformation can induce significant atomic mixing in binary alloys.
• Heat of mixing and lattice mismatch are key predictors of mixing.
• Dislocation glide is the primary mechanism for forced atomic mixing.