The Specific Heats and Resistivities of Molybdenum, Tantalum, and Rhenium From Low to Very High Temperatures

A second melting temperature occurs at a temperature Tn+ higher than Tm in glass-forming melts after heating them from their glassy state. The melting entropy is reduced or increased depending on the thermal history and on the presence of antibonds or bonds up to Tn+. Recent MD simulations show full melting at Tn+ = 1.119Tm for Zr, 1.126Tm for Ag, 1.219Tm for Fe and 1.354Tm for Cu. The non-classical homogeneous nucleation model applied to liquid elements is based on the increase of the Lindemann coefficient with the heating rate. The glass transition at Tg and the nucleation temperatures TnG of glacial phases are successfully predicted below and above Tm. The glass transition temperature Tg increases with the heating rate up to Tn+. Melting and crystallization of glacial phases occur with entropy and enthalpy reductions. A universal law relating Tn+ and TnG around Tm shows that TnG cannot be higher than 1.293Tm for Tn+= 1.47Tm. The enthalpies and entropies of glacial phases have singular values, corresponding to the increase of percolation thresholds with Tg and TnG above the Scher and Zallen invariant at various heating and cooling rates. The G-phases are metastable up to Tn+ because the antibonds are broken by homogeneous nucleation of bonds.

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“…The Re solidification was observed at 2620 K for T m = 3458 K with undercooling (∆T) = 838 K. The heat capacity was given [ 89 ] by Equation (12):

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Section: The Free Fall Solidification Of Tantalum and Rhenium Droplets Via Glacial Phasesmentioning

confidence: 99%

Prediction of Second Melting Temperatures Already Observed in Pure Elements by Molecular Dynamics Simulations

Tournier

Ojovan

2021

Materials

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“…Data for UOj "were taken from Belle's computationi^^/ for steel from standard sources, and for niobium and tantalum from Ref. 28. Values of heat transfer were obtained as a function of temperature from the cooling curve for each thermocouple record trace as follows: First, a convenient increment of temperature (of the order of 150°C) was selected.…”

Section: Analysis a Temperature Calculationsmentioning

confidence: 99%

STUDIES OF FAST REACTOR FUEL ELEMENT BEHAVIOR UNDER TRANSIENT HEATING TO FAILURE. II. INPILE EXPERIMENTS ON UO$sub 2$ SAMPLES IN THE ABSENCE OF COOLANT

Dickerman¹,

Robinson²,

Sowa³

et al. 1965

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Thermodynamic Properties of Tantalum

Arblaster

2018

J. Phase Equilib. Diffus.

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The Specific Heats and Resistivities of Molybdenum, Tantalum, and Rhenium From Low to Very High Temperatures

Cited by 6 publications

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Prediction of Second Melting Temperatures Already Observed in Pure Elements by Molecular Dynamics Simulations

Prediction of Second Melting Temperatures Already Observed in Pure Elements by Molecular Dynamics Simulations

STUDIES OF FAST REACTOR FUEL ELEMENT BEHAVIOR UNDER TRANSIENT HEATING TO FAILURE. II. INPILE EXPERIMENTS ON UO$sub 2$ SAMPLES IN THE ABSENCE OF COOLANT

Thermodynamic Properties of Tantalum

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