Correlation between structural heterogeneity and plastic deformation for phase separating FeCu metallic glasses

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Materials Science

Background:

• Plastic deformation in metallic glasses (MGs) is poorly understood due to competing disordering and ordering processes.
• Investigating the role of structural inhomogeneity is crucial for understanding MG mechanical properties.

Purpose of the Study:

• To investigate the evolution of strain localization, short-range order (SRO), and free volume in phase-separating Fe50Cu50 metallic glasses under compression.
• To elucidate the relationship between structural inhomogeneity and plastic deformation mechanisms in MGs.

Main Methods:

• Molecular dynamics (MD) simulations were employed to model compressive deformation.
• Analysis focused on strain localization, SRO, and free volume changes in MGs with varying degrees of phase separation.

Main Results:

• Increased phase separation led to decreased free volume and increased shear strain localizations.
• Cu-centered clusters exhibited higher potential energies and Voronoi volumes, bearing larger shear strains.
• Fe-centered, pentagon-rich clusters in Cu-rich regions appeared to resist shear transformation.

Conclusions:

• The interplay between structural relaxation ordering and shear stress drives Voronoi volume changes (dilatation or annihilation).
• Structural inhomogeneity significantly impacts the deformation mechanisms of metallic glasses.
• Findings enhance understanding of the structure-property relationships in MGs.