Ti-6Al-4V (TA6V) titanium alloy is widely used in industrial applications such as aeronautic and aerospace due to its good mechanical properties at high temperatures. Experiments on two different resistive pulse heating devices (CEA Valduc and TU-Graz) have been carried out in order to study thermophysical properties (such as electrical resistivity, volume expansion, heat of fusion, heat capacity, normal spectral emissivity, thermal diffusivity, and thermal conductivity) of both solid and liquid Ti-6Al-4V. Fast timeresolved measurements of current, voltage, and surface radiation and shadowgraphs of the volume have been undertaken. At TU-Graz, a fast laser polarimeter has been used for determining the emissivity of liquid Ti-6Al-4V at 684.5 nm and a differential scanning calorimeter (DSC) for measuring the heat capacity of solid Ti-6Al-4V. This study deals with the specific behavior of the different solid phase transitions (effect of heating rate) and the melting region, and emphasizes the liquid state (T >2000 K).

This article reports the first comprehensive results obtained from a fully functional, recently established infrared spectral-emissivity measurement facility at the National Institute of Standards and Technology (NIST). First, sample surface temperatures are obtained with a radiometer using actual emittance values from a newly designed sphere reflectometer and a comparison between the radiometer temperatures and contact thermometry results is presented. Spectral emissivity measurements are made by comparison of the sample spectral radiance to that of a reference blackbody at a similar (but not identical) temperature. Initial materials selected for measurement are potential candidates for use as spectral emissivity standards or are of particular technical interest. Temperature-resolved measurements of the spectral directional emissivity of SiC and Pt-10Rh are performed in the spectral range of 2-20 µm, over a temperature range from 300 to 900 • C at normal incidence.Further, a careful study of the uncertainty components of this measurement is presented.

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The National Institute of Standards and Technology (NIST) has developed a new facility for the characterization of the infrared spectral emissivity of samples between 150 and 1,000 • C. For accurate measurement of the sample surface temperatures above 150 • C, the system employs a high-temperature reflectometer to obtain the surface temperature of the sample. This technique is especially useful for samples that have significant temperature gradients due to the thermal conductivity of the sample and the heating mechanism used. The sample temperature is obtained through two measurements: (a) an indirect sample emissivity measurement with an integrating sphere reflectometer and (b) a relative radiance measurement (at the same wavelengths as in (a)) of the sample as compared to a blackbody source. The results are combined with a knowledge of the blackbody temperature and Planck's law to obtain the sample temperature. The reflectometer's integrating sphere is a custom design that accommodates the sample and heater to allow reflectance measurements at temperature. The sphere measures the hemispherical-nearnormal (8 • ) reflectance factor of the sample compared relative to a previously calibrated room-temperature reference sample. The reflectometer technique of sample temperature measurement is evaluated with several samples of varying reflectance. Temperature results are compared with values simultaneously obtained from embedded thermocouples and temperature-drop calculations using a knowledge of the sample's thermal conductivity.