Estimation of Kauzmann temperature and isenthalpic temperature of metallic glasses

摘要

We propose expressions for the estimation of the isenthalpic temperature T-0 (T-0 = alpha T-m, alpha is a semi-empirical parameter and 0 <= alpha < 1, T-m is the solidus temperature) and the Kauzmann temperature T-k (T-k = T-m exp(alpha - 1)) for glass forming alloys. It is found that T-k estimated by T-k = T-m exp(alpha - 1) is in agreement with that directly calculated from the heat capacity data, indicating that T-k = T-m exp(alpha - 1) can be used to estimate T-k of glass forming alloys. T-0 estimated by T-0 = alpha T-m, on the other hand, widely deviates from that of directly calculated from the heat capacity data. This suggests that the enthalpy difference of the under-cooled liquid and the crystal might be a nonlinear function of the temperature below T-k. Moreover, the Gibbs free energy difference Delta G is not sensitive to the deviation of alpha.