Atomic-Level Structural Characteristics of β-Relaxation in Metallic Glasses.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Physical Chemistry

Background:

• Beta-relaxation is critical for glass properties but poorly understood due to detection limits.
• Understanding beta-relaxation is key to controlling mechanical properties and structural heterogeneity in glasses.

Purpose of the Study:

• To experimentally and theoretically characterize beta-relaxation in metallic glasses.
• To elucidate the structural origins and dynamic behavior of beta-relaxation.

Main Methods:

• In situ synchrotron radiation X-ray diffraction and absorption techniques were employed.
• Molecular dynamics simulations were used to analyze atomic motions and structural features.
• Cyclic heating experiments investigated the reversibility of beta-relaxation.

Main Results:

• Beta-relaxation correlates with the evolution of cluster structures in metallic glasses.
• Fast atomic motions, specific Voronoi polyhedra, and excess free volume are linked to beta-relaxation.
• Evidence for "irreversible" beta-relaxation, which can be reactivated by rejuvenation, was found.

Conclusions:

• The study unveils the origin of beta-relaxation through experimental and theoretical structural analysis.
• This work establishes a new framework for investigating beta-relaxation in glasses.
• Findings provide insights into controlling glass properties via relaxation dynamics.