Pore configuration landscape of granular crystallization

Area of Science:

• Physics of granular materials
• Complex systems dynamics
• Materials science

Background:

• Understanding disorder-order transitions in granular assemblies is crucial for technological applications.
• Previous research focused on crystalline pattern symmetry, neglecting emergence and growth mechanisms.
• The grain-scale dynamics of granular crystallization remain largely unexplored.

Purpose of the Study:

• To investigate the grain-scale mechanisms governing the disorder-order transition in granular crystallization.
• To explore the emergence and growth of crystalline structures from irregular grain clusters.
• To characterize the topological configurations during granular crystallization and melting.

Main Methods:

• Utilized X-ray tomography for high-resolution imaging of granular packings.
• Employed persistent homology to map grain topological configurations.
• Conducted numerical simulations to study crystallization and melting dynamics.

Main Results:

• Developed topological maps of grain configurations in partially crystallized packings.
• Observed similar topological maps during the dynamic melting of perfect crystals.
• Identified key formation mechanisms for tetrahedral and octahedral pores, the building blocks of crystals.
• Demonstrated that these mechanisms explain changes in topological maps during crystallization.

Conclusions:

• Persistent homology provides insights into granular crystallization dynamics at the grain scale.
• The study elucidates pore formation mechanisms and their role in crystal growth.
• The findings offer continuous deformation pathways representative of crystallization dynamics.