Early-time particle dynamics and non-affine deformations during microstructure selection in solids

Area of Science:

• Materials Science
• Condensed Matter Physics
• Statistical Mechanics

Background:

• Solid-solid transitions involve particle groups deforming non-affinely.
• Non-affine zones (NAZ) dynamics dictate the resulting mesoscale microstructure.
• Understanding particle behavior within NAZ is crucial for predicting material properties.

Purpose of the Study:

• Investigate early-time dynamics of individual particles within NAZ during solid-solid transitions.
• Characterize how transition temperature influences particle behavior.
• Connect particle dynamics to microstructural evolution and macroscopic properties.

Main Methods:

• Focus on early-time dynamics of individual particles in NAZ during nucleation events.
• Analyze particle trajectories and their correlation with internal stresses.
• Utilize a dynamical order parameter to characterize trajectory space.

Main Results:

• Particle dynamics within NAZ are heterogeneous, featuring intermittent jamming and flow.
• At low temperatures, active particle dynamics are ballistic, driving transformations via string-like correlated movements.
• An abrupt transition from ballistic to diffusive dynamics occurs with increasing temperature, independent of diffusion coefficient.
• This dynamical transition coincides with a discontinuous microstructural change.

Conclusions:

• Early-time particle dynamics in NAZ exhibit distinct temperature-dependent regimes.
• The observed dynamical transition is linked to microstructural changes and potentially to glass transitions.
• Findings offer insights into the rheology of soft and granular matter.