3D Phase Field Modeling of Multi-Dendrites Evolution in Solidification and Validation by Synchrotron X-ray Tomography

Area of Science:

• Materials Science
• Metallurgy
• Physical Chemistry

Background:

• Understanding alloy solidification is crucial for material properties.
• Dendritic growth and coarsening are key microstructural evolution processes.
• Al-15 wt.% Cu alloy serves as a model system for studying these phenomena.

Purpose of the Study:

• To investigate the dynamics of multi-dendrite concurrent growth and coarsening in an Al-15 wt.% Cu alloy.
• To compare phase field simulations with experimental X-ray micro-tomography data.
• To elucidate coarsening mechanisms under varying solidification conditions.

Main Methods:

• Utilized a computationally efficient 3D phase field model.
• Employed real-time synchrotron X-ray micro-tomography for experimental validation.
• Performed high-fidelity multi-dendrite simulations.

Main Results:

• Direct comparison of simulations and tomography quantified growth and coarsening importance.
• Identified a shift in dominant coarsening mechanisms (e.g., coalescence) at ~0.70 solid volume fraction.
• Observed that multi-dendrite coarsening follows Lifshitz-Slyozov-Wagner theory with n=4.3.

Conclusions:

• Phase field modeling and tomography are effective tools for studying alloy solidification.
• Coarsening mechanisms transition with increasing solid fraction.
• The observed coarsening kinetics deviate slightly from classical theory, suggesting system-specific factors.