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- Mukai, K., et al.
(author)
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Surface tension of liquid alloys - A thermodynamic approach
- 2008
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In: Metallurgical and materials transactions. B, process metallurgy and materials processing science. - : Springer Science and Business Media LLC. - 1073-5615 .- 1543-1916. ; 39:4, s. 561-569
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Journal article (peer-reviewed)abstract
- A formula is derived to describe the surface tensions of binary and dilute multicomponent alloys such as iron alloys. It was thermodynamically proved that the surface tension can be described by a function of the concentrations of the alloy components in bulk phase through the use of thermodynamic parameters. The formula was applied to the binary alloys, Fe-O-N and Fe-O-S systems. The described surface tensions were found to be in good agreement with the measured values.
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| 4. |
- Aune, Ragnhild E., et al.
(author)
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Measurement of Thermophysical Properties of Liquid Metallic Alloys in a Ground- and Microgravity Based Research Programme - the ThermoLab Project
- 2005
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In: Microgravity, science and technology. - 0938-0108 .- 1875-0494. ; 16:1-4, s. 7-10
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Journal article (peer-reviewed)abstract
- The ThermoLab project is concerned with the measurement of the thermophysical properties of industrial alloys in the liquid phase. The project combines long and short duration microgravity measurements based on containerless processing with an electromagnetic levitation device and a ground based experimental programme using conventional and containerless processing techniques. An overview of the project and representative results from the ground based experimental programme are given. Alloys investigated included Ni-based, Fe-based, a Cu-Sn-Mg alloy and a gamma-TiAl alloy.
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| 5. |
- Aune, Ragnhild E., et al.
(author)
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Surface Tension and Viscosity of Industrial Alloys from Parabolic Flight Experiments : Results of the ThermoLab Project
- 2005
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In: Microgravity, science and technology. - 0938-0108 .- 1875-0494. ; 16:1-4, s. 11-14
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Journal article (peer-reviewed)abstract
- The surface tension and the viscosity of a series of industrial alloys have been measured by the oscillating drop technique with an electromagnetic levitation device under reduced gravity conditions in several parabolic flights. It was demonstrated that the 20 seconds of reduced gravity available in a parabola were sufficient for melting, heating into the liquid phase, and cooling to solidification of typically 7 mm diameter metallic specimen. The surface tension and the viscosity were obtained from the frequency and the damping time constant of the oscillation which were evaluated from the temperature signal of a highresolution pyrometer. Alloys processed included steels, Ni-based superalloys, and Ti-alloys which were supplied by industrial partners to the project. Three to four parabolas were sufficient to obtain the surface tension and the viscosity over a large range in temperature.
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| 6. |
- Aune, Ragnhild E., et al.
(author)
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Thermophysical properties of IN738lc, MM247lc and CMSX-4 in the liquid and high temperature solid phase
- 2005
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In: Superalloys 718, 625, 706 and Derivatives, Proceedings. - : TMS. ; , s. 467-476
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Conference paper (peer-reviewed)abstract
- Thermophysical properties of the Ni-based superalloys CMSX-4, IN738LC, and MM247LC have been measured in the liquid and high-temperature solid phase. Properties included calorimetric, thermal transport, the surface tension, and the viscosity. Experiments have been performed in ground-based laboratory using classical calorimetry and rheometry as well as under reduced gravity conditions in an electromagnetic levitation device on board parabolic flights. In this contribution, an overview of the various properties of three Ni-based superalloys is given with emphasis on the surface tension and viscosity as obtained from the parabolic flight experiments. The measurements were performed within a program called ThermoLab dedicated to the measurement of thermophysical properties of industrial alloys.
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- Fecht, H. -J, et al.
(author)
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Thermophysical properties of liquids : Modelling and non-metallic materials
- 2005
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In: ESA SP. - 0379-6566 .- 1609-0438. ; :1281, s. 24-35
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Journal article (peer-reviewed)abstract
- The accurate knowledge and high-precision measurements of the thermophysical properties of liquids is necessary for the numerical modeling of industrial processes where the solid-liquid phase transformation plays a crucial role. The reduction of magnetic levitation forces in microgravity leads either to a significant improvement in accuracy or makes the measurement possible in the first place. High-precision measurements on chemically highly reactive melts require containerless processing using non-contact diagnostic tools. Scientific precursor experiments were conducted in the TEMPUS containerless processing facility during the Spacelab IML-2 and MSL-1 missions, also.
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| 8. |
- Seetharaman, Seshadri, et al.
(author)
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Estimation of liquidus temperatures for multicomponent silicates from activation energies for viscous flow
- 2000
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In: Metallurgical and Materials Transactions. A. - 1073-5623 .- 1543-1940. ; 31:1, s. 111-119
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Journal article (peer-reviewed)abstract
- This article considers the viscous-flow phenomenon in molten silicate melts in the vicinity of their liquidus temperatures. An agglomeration of ionic species occurs in the liquid slag with decreasing temperatures and results in an increase in the viscosity and the activation energy for viscous flow. The latter was found to be nonlinear, increasing rapidly as the temperature is approached wherein a solid phase is likely to separate from the liquid. The second derivative of the activation energy for viscous flow with respect to temperature was found to show a discontinuity in the vicinity of the liquidus temperature. This has been verified in the case of viscous flow for both pure water and CaO-SiO2 melts. Experimental data for the viscosities, of complex silicate melts and mold fluxes have also demonstrated the occurrence of a discontinuity in the second-derivative function, which is in accordance with the liquidus temperature as determined by differential thermal analysis (DTA). Thus, the second derivative offers a useful way of estimating the liquidus temperatures of multicomponent silicates, which are often difficult to determine due to supercooling effects.
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| 9. |
- Sridhar, S., et al.
(author)
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Viscosity estimation models for ternary slags
- 2001
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In: Steel research. - : Wiley. - 0177-4832. ; 72:1, s. 3-10
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Journal article (peer-reviewed)abstract
- Five models to estimate slag viscosity have been compared with the experimental data obtained using the rotating cylinder method. The comparison was made for four ternary silicate systems, viz. FeO-MgO-SiO2, CaO-MnO-SiO2, FeO-MnO-SiO2 and CaO-Feo-SiO2. The KTH model and the model using the Gibbs energy of mixing have been found successful in estimating the slag viscosity. On the other hand, the comparisons of the experimental results with the calculated viscosity using the Riboud, Urbain and NPL models have shown poor agreement. While the limited number of the data points used for parameter optimisation would be one of the reasons for the failure of the Riboud and NPL models when applied for these ternary systems, the description of the slag composition in Urbain's approach could probably explain the disagreement between the estimated and experimental viscosity. Further studies are needed for the KTH model to accommodate fluorides in the model structure.
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