Combined DSC and Pulse-Heating Measurements of Electrical Resistivity and Enthalpy of Tungsten, Niobium, and Titanium

Wilthan, Boris; Cagran, Claus; Pottlacher, Gernot

doi:10.1007/s10765-005-6682-z

Cited by 40 publications

(22 citation statements)

References 14 publications

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“…For the data (Eqs. 8,9) depicted as dotted lines, the electrical signals during the pulse-heating are merged with temperature data from the DSC measurement via enthalpy; for details, see also [1].…”

Section: Resultsmentioning

confidence: 99%

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Thermophysical Properties of a Chromium–Nickel–Molybdenum Steel in the Solid and Liquid Phases

et al. 2007

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Numerical simulation of vacuum arc re-melting, pressurized or protective electro-slag re-melting, and ingot casting have become quite important in the metal industry. However, a major drawback of these simulation techniques is the lack of accurate thermophysical properties for temperatures above 1,500 K. Heat capacity, heat of fusion, density, and thermal conductivity are important input parameters for the heat transfer equation. Since, direct measurements of thermal conductivity of alloys in the liquid state are almost impossible, its estimation from electrical conductivity using the Wiedemann-Franz law is very useful. The afore-mentioned thermophysical properties of several steels are investigated within the context of an ongoing project. Here, we present a full set of thermophysical data for the chromium-nickel-molybdenum steel meeting the standard DIN 1.4435 (X2CrNiMo18-14-3); these values will be used by our partner to simulate various re-melting and solidification processes. Wire-shaped samples of the steel are resistively volume-heated, as part of a fast capacitor discharge circuit. Time-resolved measurements with sub-µs resolution of current through the specimen are performed with a Pearson probe. The voltage drop across the specimen is measured with knife-edge contacts and ohmic voltage dividers, the temperature of the sample with a pyrometer, and the volumetric expansion of the wire with a fast acting CCD camera. These measurements enable the heat of fusion, the heat capacity, and the electrical resistivity to be determined as a function of temperature in the solid and liquid phases. The thermal conductivity and thermal diffusivity are estimated via the Wiedemann-Franz law.

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Section: Resultsmentioning

confidence: 99%

“…For further information on the pulse heating circuit and the DSC, as well as for more details of the data evaluation, see [1]. Information regarding the CCD-Camera is given in [2].…”

Section: Measurementsmentioning

confidence: 99%

Thermophysical Properties of a Chromium–Nickel–Molybdenum Steel in the Solid and Liquid Phases

et al. 2007

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“…25 Recently developed quasi-adiabatic nanocalorimeters can operate at very high heating rates [26][27][28][29] because of very small addenda and sample heat capacities. Cooling rate, which is not controlled for the quasi adiabatic systems, is limited by total heat capacity, sample size, and heat losses.…”

Section: Introductionmentioning

confidence: 99%

Scanning Nanocalorimetry at High Cooling Rate of Isotactic Polypropylene

et al. 2006

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A wide set of cooling scans and subsequent melting behavior of isotactic polypropylene (i-PP) were investigated using differential scanning calorimetry and nanocalorimetry at very high cooling rate. The latter technique offers, indeed, the distinctive possibility to perform heat capacity measurements at rates of more than 1000 K/s, both in cooling and in heating, to characterize the crystallization. When the i-PP sample was solidified with cooling rate larger than 160 K/s, a novel enthalpic process was observed that was related to the mesomorphic phase formation. Furthermore, at cooling rates higher than 1000 K/s, the i-PP sample did not crystallize neither in the R nor in the mesomorphic form. The subsequent heating scan starting from -15°C showed an exothermic event, between 0 and 30°C, ascribed to the mesophase cold crystallization.

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“…The passage of an electrical current of about 10 000 A leads to heating rates up to 10 8 K·s −1 . Due to this rapid heating, the specimen maintains its cylindrical shape even in the liquid phase until the boiling point is reached where the specimen explodes as a result of the intense volume increase [5][6][7].…”

Section: Experimental Methodsmentioning

confidence: 99%

Thermophysical Properties of Manganin (Cu86Mn12Ni2) in the Solid and Liquid State

et al. 2015

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Manganin is the trademark name of the alloy Cu86Mn12Ni2. Despite its frequent usage in manufacturing processes, literature data are scarce particularly at higher temperatures. This work presents a set of thermophysical data of this alloy in a temperature range above its classic area of application up to the end of its liquid phase. For investigating the alloy, four examination setups were employed. Using differential thermal analysis, solidus and liquidus temperatures were obtained. In the solid phase, the electrical resistivity as a function of temperature was determined by a four-point probe positioned in a furnace. Thermal expansion was measured with a high-resolution two-beam laser dilatometer based on Michelson-interferometry and thereby density was calculated. The liquid state was investigated using a µs-ohmicpulse-heating setup. Wire-shaped specimens were resistively volume heated as part of an electrical discharge circuit. Measured quantities were the current through the specimen, the voltage drop along the specimen, the surface radiance by a pyrometer, and the thermal expansion with an adapted CCD camera system. On the basis of these measurements, temperature-dependent thermophysical properties of enthalpy, isobaric heat capacity, electrical resistivity, and density are obtained. Additionally the thermal conductivity and thermal diffusivity are estimated in the high-temperature range applying the Wiedemann-Franz law.

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Combined DSC and Pulse-Heating Measurements of Electrical Resistivity and Enthalpy of Tungsten, Niobium, and Titanium

Cited by 40 publications

References 14 publications

Thermophysical Properties of a Chromium–Nickel–Molybdenum Steel in the Solid and Liquid Phases

Thermophysical Properties of a Chromium–Nickel–Molybdenum Steel in the Solid and Liquid Phases

Scanning Nanocalorimetry at High Cooling Rate of Isotactic Polypropylene

Thermophysical Properties of Manganin (Cu86Mn12Ni2) in the Solid and Liquid State

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