Phase-field model for crystallization in alkali disilicate glasses; Li
O-2SiO
, Na
O-2SiO
and K
O-2SiO
Kawaguchi, Munemichi
; Uno, Masayoshi*
This study developed phase-field method (PFM) technique in oxide melt system by using a new mobility coefficient (
). The crystal growth rates (
) obtained by the PFM calculation with the constant
were comparable to the thermodynamic driving force in normal growth model. The temperature dependence of the
was determined from the experimental crystal growth rates and the
. Using the determined
, the crystal growth rates (
) in alkali disilicate glasses, Li
O-2SiO
, Na
O-2SiO
and K
O-2SiO
were simulated. The temperature dependence of the
was qualitatively and quantitatively so similar that the PFM calculation results demonstrated the validity of the
. Especially, the
obtained by the PFM calculation appeared the rapid increase just below the thermodynamic melting point (
) and the steep peak at around
-100 K. Additionally, as the temperature decreased, the
apparently approached zero ms
, which is limited by the
representing the interface jump process. Furthermore, we implemented the PFM calculation for the variation of the parameter
in the
. As the
increased from zero to two, the peak of the
became steeper and the peak temperature of the
shifted to the high temperature side. The parameters
and
in the
increased exponentially and decreased linearly as the atomic number of the alkali metal increased due to the ionic potential, respectively. This calculation revealed that the
and
in the
were close and reasonable for each other.