Viscosity of Aluminum during the Glass Transition Process, According to Molecular Dynamics

Resumo

The behavior of the autocorrelation functions of shear stress and the kinematic viscosity coefficient during glass transition processes is studied by means of molecular dynamics using the example of liquid aluminum. A film of liquid metal cooled at a rate of 2 × 10¹² K/s is simulated. The dependence of the kinematic viscosity coefficient on temperature is obtained using the Green–Kubo formula. Over long periods of time, the behavior of the autocorrelation functions is approximated by a power-law dependence throughout the range of temperatures. The dependence of the exponent on temperature, which enables us to estimate the temperature of the transition from the liquid to the amorphous state (it agrees with the temperature from the calorimetric criterion), is given. The temperature of the transition to glass is determined. When it is lower than that of the glass transition, features of a solid body appear: shear stress is maintained and transverse oscillations arise.