Abstract
All materials are vitrified by fast quenching even monoatomic substances. Second melting temperatures accompanied by weak exothermic or endothermic heat are often observed at Tn+ after remelting them above the equilibrium thermodynamic melting transition at Tm. These temperatures, Tn+, are due to the breaking of bonds (configurons formation) or antibonds depending on the thermal history, which is explained by using a nonclassical nucleation equation. Their multiple existence in monoatomic elements is now demonstrated by molecular dynamics simulations and still predicted. Proposed equations show that crystallization enthalpy is reduced at the temperature Tx due to new vitrification of noncrystallized parts and their melting at Tn+. These glassy parts, being equal above Tx to singular values or to their sum, are melted at various temperatures Tn+ and attain 100% in Cu46Zr46Al8 and 86.7% in bismuth. These first order transitions at Tn+ are either reversible or irreversible, depending on the formation of super atoms, either solid or liquid.
Highlights
Liquid–liquid phase transitions occur in glass-forming melts below and above Tm, the equilibrium thermodynamic melting transition of crystals
Phase 3 formation in liquid elements via first order transitions, and the second melting temperatures observed by molecular dynamics simulations at very high heating rates [73]
This paper is devoted to liquid–liquid transitions in glass-forming melts
Summary
Liquid–liquid phase transitions occur in glass-forming melts below and above Tm , the equilibrium thermodynamic melting transition of crystals. Phase 3 formation in liquid elements via first order transitions, and the second melting temperatures observed by molecular dynamics simulations at very high heating rates [73]. The question of their observation at low heating rates was raised, considering that the crystallization enthalpy of these elements would be reduced and recovered via liquid–. This paper is devoted to the second vitrification of melt fractions at first order transition temperatures, Tx , coexisting with crystals formation and predictions of multiple melting temperatures, Tn+ , of this glassy fraction above Tm from singular enthalpies of glassforming melts using a renewed completed classical nucleation equation and the configuron concept in relation with percolation thresholds.
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