NiTi 2 , a New Liquid Glass.

Many endothermic liquid-liquid transitions, occurring at a temperature T n+ above the melting temperature T m , are related to previous exothermic transitions, occurring at a temperature T x after glass formation below T g , with or without attached crystallization and predicted by the nonclassical homogenous nucleation equation. A new thermodynamic phase composed of broken bonds (configurons), driven by percolation thresholds, varying from ~0.145 to Δε, is formed at T x, with a constant enthalpy up to T n+ . The liquid fraction Δε is a liquid glass up to T n+ . The solid phase contains glass and crystals. Molecular dynamics simulations are used to induce, in NiTi 2 , a reversible first-order transition by varying the temperature between 300 and 1000 K under a pressure of 1000 GPa. Cooling to 300 K, without applied pressure, shows the liquid glass presence with Δε = 0.22335 as memory effect and T n+ = 2120 K for T m = 1257 K.