Observation of wavelength shifts in ruby under shock compression to 36 GPa by time-resolved luminescence spectroscopy

Abstract

We have measured time-resolved luminescence spectra of ruby crystal subjected to impact-induced shock compression along the a axis to 36.3 GPa, recording the effect of shock and release waves on ruby R lines as streaks. Near the Hugoniot elastic limit ͑HEL͒, ruby luminescence lines blur, but above the HEL, blurring disappears and a clear image returns with the temporal behavior of luminescence lines differing from that in elastic region. Above the HEL, the luminescence intensity of shock-compressed ruby crystal decreases with increasing shock pressure.

How the Toughest Inorganic Fullerene Cages Absorb Shockwave Pressures in a Protective Nanocomposite: Experimental Evidence from Two In Situ Investigations

“…From the luminescence results, we can distinguish the two different types of behavior for our samples (Figure and Table ): samples A, B, and C exhibiting a stronger and sharper shifted R1 line accompanied by a negative shift, signifying the typical elastic region signal; samples D and E (containing IF-WS 2 ) having similarly very weak, broad, and short shifted R1 signal, evidencing the inelastic region characteristics . These results have confirmed that for samples D and E, the ruby crystal windows responded inelastically in the elastic region below the HEL of ruby.…”

“…However, the compression-shifted R1 signal for sample D (Figure f) was much weaker than that of sample B (Figure b), consistent with the more blurred signals in the streak image. Significantly, the intensity of the shifted R1 was much weaker, with only 32% intensity compared to that at ambient pressure (Figure d), and the very weak, broad, and short characteristics of such shifted R lines were indicative of an inelastic region signal . This is very surprising, as the shock pressure was below the HEL of ruby.…”

“…For sample B, the 3.29 nm shift of R1 (Figure b) corresponded to a shock pressure of ∼12.4 GPa. This was below the Hugoniot elastic limit (HEL) of ruby, which was 14 GPa, suggesting the ruby window was shock compressed elastically . In addition, the shifted R1 line is very strong, with intensity almost 66% of intensity for the ambient R1 line.…”

“…The negatively shifted R line signals observed at around 1 μs (Figure a,c) were attributed to the interaction of rarefaction from ruby edges . Based on the pressure-shift characteristics of the ruby crystal, , we can then determine the shock pressures on the ruby, corresponding to each exact stage of the impact compression.…”

“…IF-WS 2 nanoparticles have been incorporated with a wide range of polymer matrices previously, , and they have effectively improved thermal, mechanical, and tribological properties, even the toughness of the composites; however, there were hardly any reports focusing on other matrices reinforced by these IF nanoparticles. Here, we report two very innovative and specialized in situ impact techniques in geophysics: the time-resolved luminescence , and the velocity interferometer system for any reflector (VISAR) techniques, , combined with postshock analyses, to investigate the impact performance of such IF-WS 2 containing Al model nanocomposites and to scrutinize their precise roles in impacts, by contrasting with the conventional bulk 2H-WS 2 (the hexagonal WS 2 platelets) composites.…”