A twin cell model for computation of glass transition temperature of quaternary thin film metallic glasses

• Twin cell model correlating the compositional dependence of glass transition temperature for two TFMG systems.
• Model combines hydrodynamic equations, transition state theories and icosahedral symmetry based analytical calculations.
• Diffusion coefficients computed from the twin cell model as a function of temperature.
• Model predicts substantial lowering of glass transition with the increase in Ni content.
• Predicted trend substantiated by Johnson's study on lowering of Laves Phases.

We present a novel twin cell model to evaluate the effect of structure and composition on glass transition of Zr–Ti–Cu–Ni and Zr–Al–Cu–Ni quaternary thin film metallic glasses. Starting from Navier–Stokes equation the statistical average velocity was evaluated under the condition of ensemble equality. This was used to compute the diffusion lengths and the diffusion coefficients as a function of temperature, where from the glass transition temperature was estimated. An increasing Ni concentration was seen to lower the glass transition by up to 200 K, a trend substantiated by Johnson's studies on the lowering of Laves phase with increasing Ni concentration.