Thermophysical Properties of Solid Phase Zirconium at High Temperatures

Abstract

This paper presents experimental results on the thermophysical properties of relatively pure polycrystalline zirconium samples in the solid phase from room temperature up to near the melting point. The specific heat capacity and specific electrical resistivity were measured from 290 to 1970 K, the hemispherical total emissivity from 1400 to 2000 K, the normal spectral emissivity from 1480 to 1940 K, and the thermal diffusivity in the range from 290 to 1470 K. From these data, the thermal conductivity and Lorentz number were computed in the range from 290 to 1470 K. For necessary corrections the most recent values of the linear thermal expansion from the literature have been used. Subsecond pulse calorimetry for measuring heat capacity, specific electrical resistivity, and both emissivities and the laser flash method for measuring thermal diffusivity were applied. Samples in the form of a thin rod and in the form of a thin disk were used in the first and second methods, respectively. Measurement uncertainties were generally about 3% for heat capacity, 1.6% for specific electrical resistivity, 3-10% for the two emissivities, and from less than 1% up to 6% for thermal diffusivity. All the results are discussed in reference to available literature data.

Phase Transformation Contributions to Heat Capacity and Impact on Thermal Diffusivity, Thermal Conductivity, and Thermoelectric Performance

“…Thus, even though these are steady‐state materials properties where no net phase transformation may be taking place, microscale atomic fluctuations taking place at timescales of heat fluctuations give rise to an increase in the heat capacity that decreases the thermal diffusivity but has little effect on the thermal conductivity. This applies even to nominally isothermal transformations in single component systems, such as the hcp → bcc phase transition of zirconium at 1140 K …”

Exploring Thermal and Mechanical Properties of Selected Transition Elements under Extreme Conditions: Experiments at High Pressures and High Temperatures

“…Least-squares fitting of the measured data to the numerical heat-transfer model produced relative values of thermal conductivities that are consistent with ambient conditions data available in the literature (Kirby, 1991;Milošević and Maglić, 2006). …”

“…The main consideration in the following type of experiment, as discussed in the previous sections, is that the two metal samples are to be loaded with identical thermal (Kirby, 1991;Milošević and Maglić, 2006), were loaded into a DAC using a side-by-side geometry as shown in Figure 2.18.…”

High-resolution inductive measurement of electrical resistivity and density of electromagnetically levitated liquid metal droplets

“…(14) and (15) has to be determined with the help of a spherical calibration sample of well-known electrical resistivity or radius. Very convenient for this is a solid zirconium (Zr) test sphere of known radius a Zr (300 K) at room temperature because on the one hand, the resistivity ρ Zr (T ) and thermal expansion da Zr /dT of solid Zr is over a larger temperature range very well-known from the literature 27,28 and, on the other hand, the solid-solid phase transition of Zr at T ZrPhase = 1148 K can very well be used for the likewise necessary calibration of the pyrometric sample temperature measurement.…”