Enthalpy measurements of the solid high-temperature β-phase of titanium and zirconium by levitation drop calorimetry

Rösner-Kuhn, Michael; Drewes, Karsten; Franz, Henrik; Frohberg, Martin G.

doi:10.1016/s0925-8388(00)01509-7

Cited by 26 publications

(5 citation statements)

References 4 publications

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“…We obtained a value of heat of fusion of zirconium ∆H f us ≈ 14 kJ/mol by QMD. Our calculations tend to the lower values of the enthalpy of melting measured by rapid pulse heating [78][79][80] and drop calorimetry [90,98,100] (12.8-21.5 kJ/mol).…”

Section: Enthalpymentioning

confidence: 74%

“…Above 273.15 K and up to the α-β transition temperature, the Douglas and Victor [87] enthalpy measurements (373-1124 K) were adopted after a correction to the International Temperature Scale of 1990 (ITS-90 is an approximation of the thermodynamic temperature scale that facilitates comparability and compatibility of temperature measurements internationally). Before melting, specific heat measurements of Cezairliyan and Righini [88] (1500-2100K) and Petrova et al [89] (1200-2100 K) were combined with the drop calorimetry enthalpy measurements of Rösner-Kuhnetal et al [90] (1821-2105 K).…”

Section: Enthalpymentioning

confidence: 99%

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Ab initio inspection of thermophysical experiments for zirconium near melting

Paramonov¹,

Minakov²,

Fokin³

et al. 2021

Preprint

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We present quantum molecular dynamics calculations of thermophysical properties of solid and liquid zirconium in the vicinity of melting. An overview of available experimental data is also presented. We focus on the analysis of thermal expansion, molar enthalpy, resistivity and normal spectral emissivity of solid and liquid Zr. Possible reasons of discrepancies between the firstprinciple simulations and experiments are discussed. Our calculations reveal a significant volume change on melting in agreement with electrostatic levitation experiments. Meanwhile, we confirm a low value of enthalpy of fusion obtained in some pulse-heating experiments. Electrical resistivity of solid and liquid Zr is systematically underestimated in our simulations, however the slope of resistivity temperature dependencies agrees with experiment. Our calculations predict almost constant normal spectral emissivity in liquid Zr.

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Section: Enthalpymentioning

confidence: 74%

Section: Enthalpymentioning

confidence: 99%

Ab initio inspection of thermophysical experiments for zirconium near melting

Paramonov¹,

Minakov²,

Fokin³

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…According to the levitation drop calorimetry experiment in ref. [21], the emissivity ε T =0.294 was substituted into eq. ( 5) [11].…”

Section: Density and Specific Heatmentioning

confidence: 99%

Metastable liquid properties and rapid crystal growth of Ti-Ni-Al alloy investigated by electrostatic levitation and molecular dynamics simulation

Xiao

Ruan

Lin

et al. 2021

Sci. China Technol. Sci.

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Electrostatic levitation technique and molecular dynamics simulation were performed to investigate the thermophysical properties, liquid structure and crystal growth dependence on undercooling of Ti 85 Ni 10 Al 5 alloy. The liquid Ti 85 Ni 10 Al 5 alloy was substantially undercooled up to 335 K (0.18T L ). As undercooling increased, the potential energy of the liquid alloy decreased and the alloy entered into a high metastable state. At this state, the atoms tended to bond with each other and the clusters were inclined to convert into high-coordinated clusters, as confirmed by the fraction of the high-coordinated clusters variation. The enlarged clusters and enhanced local structure stability contributed to the increase of the thermophysical parameters and crystal growth velocity, and eventually dendrite refinement. The density, the specific heat and the surface tension of liquid alloy exhibited a linear relation with temperature and the shear viscosity of liquid alloy showed exponential variation which showed good agreement with the calculation results by molecular dynamics simulation. The growth velocity first increased slowly and then dramatically once the undercooling exceeded the threshold. The achieved maximum crystal growth velocity was 12.4 m s −1 and it was up to 326 times of the value at 94 K undercooling.

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“…This indicates that weights determined by the automated weighting procedure described in section 3.1 are relatively insensitive to each other and, perhaps more surprisingly, to fluctuations in the model's parameterization. Looking at the values of the hyperparameters themselves, we can see that the Bayesian framework highly weights the measurements of Korobenko [63], Cagran [64] and Rösner-Kuhn [65] while assigning the measurements of Paradis [66] a low weight. Figures 3 and 4, which display the model predictions and experimental data sets confirm that the model prediction aligns closely with the prioritized data sets while effectively ignoring the Paradis measurements.…”

Section: Case Study: Hafniummentioning

confidence: 99%

Uncertainty quantification and propagation in CALPHAD modeling

Honarmandi

Paulson

Arróyave

et al. 2019

Modelling Simul. Mater. Sci. Eng.

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Design is about making decisions bounded by a quantifiable degree of certainty. In the context of alloy design, Integrated Computational Materials Engineering (ICME) provides the framework whereby performance requirements are ultimately transformed into alloy/processing specifications through the combination of (complex) computational models connecting processstructure-property-performance relationships and experiments. Most ICME approaches consider the models used as deterministic and thus do not provide the means to make alloy design decisions with proper confidence measures. At the root of ICME lie CALPHAD models that describe the thermodynamics and phase stability of phases under specific thermodynamic boundary conditions. To date, the vast majority of efforts within the CALPHAD community have been deterministic in that thermodynamic models and the resulting thermodynamic properties and phase diagram features do not explicitly account for the uncertainties inherent in the model formulation or in the experimental/computational data used. In this contribution, we provide an overview of the state of the field. We review major efforts thus far and we then provide a (brief) tutorial on basic concepts of uncertainty quantification and propagation (UQ/UP) in CALPHAD. We discuss the major features of frequentist and Bayesian interpretations of uncertainty and proceed with a discussion of recent case studies in which UQ has been used to parameterize models for the thermodynamic properties of phases. We follow our discussion by presenting frameworks and demonstrating the propagation of uncertainty in

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Enthalpy measurements of the solid high-temperature β-phase of titanium and zirconium by levitation drop calorimetry

Cited by 26 publications

References 4 publications

Ab initio inspection of thermophysical experiments for zirconium near melting

Ab initio inspection of thermophysical experiments for zirconium near melting

Metastable liquid properties and rapid crystal growth of Ti-Ni-Al alloy investigated by electrostatic levitation and molecular dynamics simulation

Uncertainty quantification and propagation in CALPHAD modeling

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