Strain-dependent evolution of avalanche dynamics in bulk metallic glass

Area of Science:

• Materials Science
• Condensed Matter Physics
• Non-equilibrium Systems

Background:

• Avalanche phenomena with power-law scaling are common in amorphous solids and nonequilibrium systems during deformation.
• These avalanches often display scale invariance, suggesting connections to critical phenomena, but their origins are not fully understood.

Purpose of the Study:

• To experimentally investigate avalanche characteristics and evolution in bulk metallic glass (BMG) during deformation.
• To explore the underlying mechanisms driving these avalanches and their relationship to scaling laws.

Main Methods:

• In situ acoustic emission techniques were employed to monitor avalanche events.
• Surface morphology and spectral analysis of avalanche signals were conducted on BMG samples.
• Quantitative analysis of strain-dependent avalanche characteristics was performed.

Main Results:

• Abundant avalanche events were observed from microplastic deformation to sample failure.
• Avalanches followed a power-law distribution with an exponent decreasing with increasing strain.
• A strain-mediated avalanche scaling mechanism was identified, highlighting the importance of additional coefficients in finite-size scaling.

Conclusions:

• Avalanches in BMG are driven by nanoscale microstructural adjustments, not macroscopic events like crack propagation.
• The findings suggest that theoretical models beyond standard finite-size scaling are needed to fully explain avalanche dynamics.
• Further research into the microscopic origins of avalanches in amorphous solids is encouraged.