β-Relaxation and Crystallization Behaviors in a Pulse-Current-Thermoplastic-Formed La-Based Bulk Metallic Glass

Area of Science:

• Materials Science
• Condensed Matter Physics
• Physical Chemistry

Background:

• Bulk metallic glasses (BMGs) are advanced materials with unique properties.
• Understanding structural relaxations is key to controlling BMG behavior.
• Atomic structure rejuvenation can enhance material properties.

Purpose of the Study:

• To investigate the effect of pulse current thermoplastic forming on BMG atomic structure.
• To analyze the influence of sub-Tg annealing on structural relaxations and crystallization.
• To establish a method for rejuvenating BMG structures.

Main Methods:

• Utilized pulse current thermoplastic forming based on joule heating.
• Applied sub-Tg annealing to BMG samples.
• Characterized atomic structure and relaxation dynamics (β- and α-relaxation).
• Studied high-temperature crystallization kinetics.

Main Results:

• Pulse forming increased free volume and enhanced β-relaxation in La-Al-Ag-Ni-Co BMG.
• Sub-Tg annealing weakened β-relaxation and isolated it from α-relaxation.
• Neither treatment significantly affected α-relaxation or crystallization kinetics.
• Demonstrated a method for BMG structural rejuvenation.

Conclusions:

• Pulse current forming is an effective technique for rejuvenating BMG atomic structures.
• Structural relaxations, particularly β-relaxation, are sensitive to processing and annealing.
• The relationship between structural relaxations and crystallization kinetics in BMGs is complex.
• Results provide insights into controlling BMG properties through structural manipulation.