Linking local microstructure to fracture location in a two-dimensional amorphous solid under isotropic strain.

Area of Science:

• Materials Science
• Physics
• Statistical Mechanics

Background:

• Brittle fracturing is a critical phenomenon across natural and industrial processes.
• Understanding atomistic dynamics during crack propagation is experimentally challenging.
• Microstructural evolution significantly influences material failure.

Purpose of the Study:

• To investigate the microstructural evolution during brittle fracture in colloidal monolayers.
• To develop and validate a predictive parameter for fracture-prone regions.
• To identify key microstructural features governing crack initiation.

Main Methods:

• Applying isotropic dilational strain to a densely packed monolayer of attractive colloidal microspheres.
• Utilizing brightfield microscopy and particle tracking for microstructural analysis.
• Developing a machine learning-based 'Weakness' parameter to quantify fracture likelihood.

Main Results:

• The 'Weakness' parameter successfully identifies regions prone to fracture.
• Local particle density emerged as a more significant predictor of fracture than orientational order.
• While Weakness predicts prone regions, crack nucleation sites remain unpredictable.

Conclusions:

• The proposed experimental approach offers novel insights into microscopic fracture processes.
• Local density is a key microstructural factor influencing brittle fracture in colloidal systems.
• This work lays the foundation for advanced studies on fracture mechanics at the microscale.