Problems of shock temperature measurements for metals by using optical radiometry method
Titel:
Problems of shock temperature measurements for metals by using optical radiometry method
Auteur:
Tan, Hua Dai, Chengda
Verschenen in:
High pressure research
Paginering:
Jaargang 21 (2001) nr. 3-4 pagina's 183-214
Jaar:
2001-12-01
Inhoud:
Several problems encountered in shock temperature measurements for metals using optical radiometry were discussed in detail. The influences of the driver/film gap upon the observed interface temperature history were formulated analytically, and the temperature relaxation behaviors at the film/window interface were also characterized. We found that the energy deposition at the driver/film gap would influence to varied degrees the film/window interface temperature profile unless the film deposited on the window can be regarded to have an infinite thickness. Modeling calculations showed that at shock pressures of a few megabars, the observed interface temperature of iron would be at least 300-600 K higher, relative to the prediction from the Grover model, provided that the gap and film were both 1 ∼ 2 pm thick. Additionally, a metal-plate sample was used to measure a reliable shock temperature based on one-dimensional heat conduction model for the plate-sample(driver)/ pm-gap/window setup we proposed. Preliminary measured results for a meteoritic iron sample (kamacite, with Fe 93.65 wt.% and Ni 6.35 wt.%) using a disc sample showed that this method was practical and effective. Finally, the “heat-resistance model” proposed by Tang et al., and the experimental measurement of the heat conductivity for a transparent window (sapphire or LiF crystal) at megabar shock pressures were discussed and commented on as well.
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