From mild to wild fluctuations in crystal plasticity

Area of Science:

• Materials Science
• Solid State Physics
• Condensed Matter Physics

Background:

• Classical models describe macroscopic crystal plasticity via uncorrelated dislocation motions, leading to Gaussian fluctuations.
• Recent studies suggest highly correlated dislocation dynamics and power-law distributed fluctuations, creating a conflicting view.
• Understanding the interplay between these dynamics is crucial for materials science.

Purpose of the Study:

• To investigate the coexistence of intermittent and continuous plastic flow in crystals.
• To reconcile the classical Gaussian fluctuation model with recent power-law findings.
• To propose a theoretical framework explaining observed plastic flow behaviors.

Main Methods:

• Acoustic emission measurements were performed on crystals with varying symmetries.
• Analysis focused on identifying and characterizing intermittent events and background fluctuations.
• Data was compared against theoretical models of dislocation dynamics.

Main Results:

• Evidence for crossover regimes in plastic flow was demonstrated.
• Strongly intermittent events were observed to coexist with a Gaussian quasiequilibrium background.
• The findings support a unified view of crystal plasticity.

Conclusions:

• Intermittent and continuous models of plastic flow are not mutually exclusive.
• A unified framework can accommodate both Gaussian and power-law fluctuation regimes.
• This research advances the understanding of macroscopic crystal plasticity and dislocation behavior.