Implicit glass model for simulation of crystal nucleation for glass-ceramics

Predicting crystal nucleation behavior in glass-ceramic materials is important to create new materials for high-tech applications. Modeling the evolution of crystal microstructures is a challenging problem due to the complex nature of nucleation and growth processes. We introduce an implicit glass model (IGM) which, through the application of a Generalized Born solvation model, effectively replaces the glass with a continuous medium. This permits the computational efforts to focus on nucleating atomic clusters or undissolved impurities that serve as sites for heterogeneous nucleation. We apply IGM to four different systems: binary barium silicate (with two different compositions), binary lithium silicate, and ternary soda lime silicate and validate our precipitated compositions with established phase diagrams. Furthermore, we nucleate lithium metasilicate clusters and probe their structures with SEM. We find that the experimental microstructure matches the modeled growing cluster with IGM for lithium metasilicate. Crystal nucleation: implicit glass model for silicate growth dynamics The evolution of growing clusters in glass-ceramic materials can be predicted computationally with an implicit glass model (IGM). An inter-disciplinary team at Corning Incorporated, the Pennsylvania State University, and ANL developed the IGM to gain insight into the underlying physical mechanism governing the nucleation process of crystal microstructures in glass-ceramic materials. The computational approach uses an extended Generalized Born Model that treats the liquid/glass matrix as an implicit solvent, thus allowing considerable computational savings. By replacing the glass with a continuous medium, the computational effort is predominantly dedicated to tracking the evolution of the nucleating atomic clusters. The method was applied to a number of solid-state systems including barium silicate, lithium disilicate, and soda lime silicate, and the IGM was validated on experimentally synthesized compounds.