Radiance temperatures (in the wavelength range 523?907 nm) of group IVB transition metals titanium, zirconium, and hafnium at their melting points by a pulse-heating technique

Abstract

The melting-point radiance temperatures (at six wavelengths in the range 523-907 nm) of the Group IVB transition metals titanium, zirconium, and hafnium were measured by a pulse-heating technique. The method is based on rapid resistive self-heating of the specimen from room temperature to its melting point in less than 1 s and on simultaneously measuring the specimen radiance temperatures every 0.5 ms with a high-speed six-wavelength pyrometer. Melting was manifested by a plateau in the radiance temperature-versus-time function for each wavelength. The melting-point radiance temperatures for a given specimen were determined by averaging the measured temperatures along the plateau at each wavelength. The melting-point radiance temperatures for each metal were determined by averaging results for several specimens at each wavelength as follows: Bascd on cstimatcs of the random and systematic errors arising from pyrometry and specimen conditions, the combined uncertainty (95',/. confidence level) in the reported values is about +8 K at each wavelength.

Ab initio inspection of thermophysical experiments for zirconium near melting

“…Moreover, for larger wavelengths the jump in normal spectral emissivity is predicted by our calculations. Our results for 650 and 900 nm agree excellently with Cezairliyan et al [111] and some other experiments for molten Zr. Good agreement of our data with Cagran et al [109] for the liquid Zr and with recent experiment by Milošević et al for β-Zr is also demonstrated.…”

“…We can see that the slope of E(λ) obtained in this work is similar to the linear fit of the experimental data by Krishnan et al [110]. Even more spectacular agreement is observed for data of Cezairliyan et al [111]. The values of normal spectral emissivity from first-principle calculations agree well with other experiments for λ = 650 [116] and 684.5 nm [109,117].…”

“…agree almost perfectly with Cezairliyan et al [111] experiment for molten Zr. There is good agreement of our data with Cagran measurements for the liquid Zr and with recent experiment by Milošević et al for β-Zr.…”

“…Wavelength, nm Zr Figure 6: Normal spectral emissivity of liquid Zr at different wavelengths. Data obtained in this work is shown as red line; black circles are experiment [110], black line is its linear approximation; black square is experiment [116], black triangle is experiment [117], black diamond is experiment [109], down triangles with line is experiment [111].…”

Спектральная Эмиссионная Способность Технического Титана Вблизи Точки Плавления

“…Литературный обзор показал, что основной массив экспериментальных данных по спектральной эмиссионной способности титана в твердой фазе исследовался в небольшом интервале длин волн и температур, а в ряде случаев исследования были ограничены единственным замером фиксированной длины волны [8][9][10].…”