Influence of Fermi energy equalization on crystal nucleation in glass melts

The energy saving produced by the equalization of Fermi energies of a crystal and a melt has been associated to the crystal formation in undercooled melts to determine the new homogeneous-nucleation critical-temperature T(2) and the new nucleation critical barrier as a function of the temperature T. Small unmelted clusters act as nuclei by reducing the critical energy barrier and the nucleation times; the glass transition temperature T(g) occurs near T = T(2). The temperature dependence of the specific heat difference of the undercooled melt with the glass, the viscosity weakening below T(g) and the nose of the temperature-time-transformation diagrams are successfully predicted. (C) 2008 Elsevier B.V. All rights reserved.