Applications of Non-Equilibrium Thermodynamics for Phase Transformation in Materials that Exhibit Glassy Transition

by Dr Tomorr Haxhimali (Lawrence Livermore National Laboratory)

Wednesday 29 Apr 2026, 13:30 → 15:30 Asia/Taipei

L124, Physics Building (NTHU)

In this talk I will start by quickly giving an overview of the glass transition and associated phase transformation like crystallization and melting for materials that exhibit complex disorder structures. These fall into two categories: i) Imposed glassy transition from overdriven conditions, like those due to rapid cooling in Additive Manufacturing f.e. or in materials at the wake of a shock wave; and ii) Complex materials with many chemical components, like high entropy alloys (HEAs) or ZBLAN glasses, whose disordered structure comes naturally at ambient conditions.

I will briefly present a Statistical Mechanics framework for the glassy transition that hints at a putative connection with the hierarchical Parisi's Tree framework that is successfully used in Spin Glasses.

I will continue with a study of the glassy transition for binary alloy during rapid solidification at different cooling rates. We use atomistic simulations and mesoscopic phase field. The latter is enhanced by the use of Extended Irreversible Thermodynamics (EIT) that captures the effect of the transient regime prevalent in these conditions. Extending this method to more complicated High Entropy Alloys will be discussed.

The last part of the talk will be dedicated to the study of the devitrification (crystallization) process in ZBLAN (ZrF4-BaF2-LaF3-ALF3-NaF) glasses. ZBLAN glasses have intermediate properties between metallic glasses and "classical" Si-based glasses. These make these glasses versatile; analogous to the semiconductors in the semiconducting industry. In fiber optics ZBLAN glasses provide superior optical properties. Difficulties in reaching these parameters are attributed to crystal imperfections during manufacturing that can be associated with the shear thinning effect and existence of convection flows in gravitational conditions. In this effort we have developped nucleation models from atomistic and experimentally informed phase-field studies, that consider convection flow and dissipative effects through viscosity. We will conclude by discussing lesson learned by the versatility of ZBLAN.

* This work was performed under the auspices of the US Dept. of Energy by Lawrence Livermore National Security, LLC under Contract DE-AC52-07NA27344. LLNL-ABS-835032