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- Abdul Abas, Riad, et al.
(författare)
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Thermal Diffusivity measurement of CMSX-4 alloy by Laser flash method
- 2007
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Ingår i: International journal of thermophysics. - : Springer Science and Business Media LLC. - 0195-928X .- 1572-9567. ; 28:1, s. 109-122
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Tidskriftsartikel (refereegranskat)abstract
- In the present work, thermal diffusivity measurements have been carried out on industrial samples of CMSX-4 nickel-base superalloy using the laser-flash method with emphasis on studying the effect of temperature and microstructure on the thermal diffusivity. The measurements were performed in the temperature range from 298 to 1623 K covering both solid as well as liquid ranges. Below 1253 K, the thermal-diffusivity values were found to increase with increasing temperature. Microstructural investigations of quenched samples revealed that below 1253 K, an ordered phase, usually referred to as the -phase was present together with the disordered fcc phase, often referred to as the γ phase. Between 1253 K and the solidus temperature, the phase was found to dissolve in the matrix alloy causing an increase in the disordering of the alloy, and thereby a small decrease in the thermal-diffusivity values. The thermal-diffusivity values of samples pre-annealed at 1573 K exhibited constancy in the temperature range from 1277 to 1513 K, which is attributed to the attainment of thermodynamic equilibrium. These equilibrium values were found to be lower than the results for samples not subjected to annealing. The thermal-diffusivity values of the alloy in the liquid state were found to be independent of temperature.
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| 2. |
- Brillo, J., et al.
(författare)
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Density and surface tension of liquid ternary Ni-Cu-Fe alloys
- 2006
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Ingår i: International journal of thermophysics. - : Springer Science and Business Media LLC. - 0195-928X .- 1572-9567. ; 27:6, s. 1778-1791
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Tidskriftsartikel (refereegranskat)abstract
- The density and surface tension of liquid Ni-Cu-Fe alloys have been measured over a wide temperature range, including the undercooled regime. A non-contact technique was used, consisting of an electromagnetic levitator equipped with facilities for optical densitometry and oscillating drop tensiometry. At temperatures above and below the liquidus point, the density and surface tension are linear functions of temperature. The concentration dependence of the density is significantly influenced by a third-order (ternary) parameter in the excess volume. The surface tensions are rather insensitive to substitution of the two transition metals Ni, Fe against each other and depend only on the copper concentration. By numerically solving the Butler equation, the surface tension of the ternary system can be derived from the thermodynamic potentials (E)G of the binary phases (Ni-Cu, Fe-Cu, Ni-Fe) alone.
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| 3. |
- Egry, I., et al.
(författare)
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Thermophysical properties of gamma-titanium aluminide : The European IMPRESS project
- 2007
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Ingår i: International journal of thermophysics. - : Springer Science and Business Media LLC. - 0195-928X .- 1572-9567. ; 28:3, s. 1026-1036
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Tidskriftsartikel (refereegranskat)abstract
- In the framework of its 6th Framework Programme, the European Union funds the Integrated Project IMPRESS, related to industrial applications of Ti-Al and Ni-Al alloys. One central task of this project is the precise determination of the relevant thermophysical properties of selected alloys for both the solid and liquid phases. The properties to be measured include thermal data such as heat of fusion, specific heat, and thermal conductivity, as well as thermophysical and transport properties such as density, surface tension, and viscosity. In addition to conventional high-temperature equipment, containerless methods are used. This article introduces the IMPRESS project, and discusses the first results obtained to date.
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| 7. |
- Kutcherov, Vladimir G.
(författare)
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Glass transition in crude oils under pressure
- 2006
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Ingår i: International journal of thermophysics. - : Springer Science+Business Media B.V.. - 0195-928X .- 1572-9567. ; 27:2, s. 467-473
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Tidskriftsartikel (refereegranskat)abstract
- The transition to the glassy state in crude oil has been investigated at high pressures by the transient hot-wire method and differential scanning calorimetry. The nine samples investigated represent the most common types of crude oils and their fractions. The range of pressures was from atmospheric to 2 GPa in the temperature range of 150–370 K. The pressure dependence of the glass transition in crude oils and oil fractions (dTg/dp) depends upon the viscosity of the system.
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| 8. |
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| 9. |
- Ricci, E., et al.
(författare)
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Density, surface tension, and viscosity of CMSX-((R)) superalloy
- 2007
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Ingår i: International journal of thermophysics. - : Springer Science and Business Media LLC. - 0195-928X .- 1572-9567. ; 28:4, s. 1304-1321
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Tidskriftsartikel (refereegranskat)abstract
- The surface tension, density, and viscosity of the Ni-based superalloy CMSX-4((R)) have been determined in the temperature ranges of 1,650-1,850 K, 1,650-1,950 K, and 1,623-1,800 K, respectively. Each property has been measured in parallel by different techniques at different participating laboratories, and the results are compared with the aim to improve the reliability of data and to identify recommended values. The following relationships have been proposed: density-rho (T) [kg.m(-3)] = 7,876 - 1.23(T - 1,654 K); surface tension-gamma (T) [mN.m(-1)] = 1,773 - 0.56 (T - 1, 654 K); viscosity-eta (T) [mPa.s] = 8.36 - 1.82 x 10(-2)(T - 1,654 K). For a comparison, surface-tension measurements on the Al-88.6 at% Ni liquid alloy with the same Al-content as the CMSX-4((R)) alloy were also performed. In addition, the surface tension and density have been theoretically evaluated by different models, and subsequently compared with new experimental data as well as with those reported in the literature. The surface-tension experimental data for the liquid CMSX-4((R)) alloy were found to be close to that of the A1-88.6 at% Ni alloy which is consistent with results from the compound formation model (CFM).
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