Abstract
The thermal history of melts leads to three liquid states above the melting temperatures Tm containing clusters—bound colloids with two opposite values of enthalpy +Δεlg × ΔHm and −Δεlg × ΔHm and zero. All colloid bonds disconnect at Tn+ > Tm and give rise in congruent materials, through a first-order transition at TLL = Tn+, forming a homogeneous liquid, containing tiny superatoms, built by short-range order. In non-congruent materials, (Tn+) and (TLL) are separated, Tn+ being the temperature of a second order and TLL the temperature of a first-order phase transition. (Tn+) and (TLL) are predicted from the knowledge of solidus and liquidus temperatures using non-classical homogenous nucleation. The first-order transition at TLL gives rise by cooling to a new liquid state containing colloids. Each colloid is a superatom, melted by homogeneous disintegration of nuclei instead of surface melting, and with a Gibbs free energy equal to that of a liquid droplet containing the same magic atom number. Internal and external bond number of colloids increases at Tn+ or from Tn+ to Tg. These liquid enthalpies reveal the natural presence of colloid–colloid bonding and antibonding in glass-forming melts. The Mpemba effect and its inverse exist in all melts and is due to the presence of these three liquid states.
Highlights
The thermodynamic transition at Tg is characterized by a second-order phase transition and a heat capacity jump defined by the derivative of the difference (εls (θ) − εgs (θ)) ∆Hm which is equal to 1.5 ∆Sm for many glass transitions with ∆Sm being the melting entropy [9]
Our models of homogeneous nucleation and configurons explained the formation of liquid phases above Tg with mean-range order disappearing at a temperature Tn+
La50 Al35 Ni15 observed with Nuclear Magnetic Resonance (NMR) at TLL = 1063 and 1033 Knight shift (Ks), respectively, occurred at the temperature Tn+ corresponding to the liquidus temperature of these two alloys
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The thermodynamic transition at Tg is characterized by a second-order phase transition and a heat capacity jump defined by the derivative of the difference (εls (θ) − εgs (θ)) ∆Hm which is equal to 1.5 ∆Sm for many glass transitions with ∆Sm being the melting entropy [9]. Our nucleation model of melting the liquid mean-range order by breaking residual bonds predicted all values of Tn+ and exothermic enthalpies at this temperature. The observation of endothermic latent heats showed the existence of three liquid states at Tm , the first one with a positive enthalpy εgs (0) × ∆Hm , the second one zero, and the third one −εgs (0) × ∆Hm , which is negative.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
