Stishovite nucleation at low shock pressures in soda-lime glass
Stishovite nucleation at low shock pressures in soda-lime glass
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DOI：
10.1016/j.actamat.2021.117124
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发表时间：
2021-08
期刊：
影响因子：
9.4
通讯作者：
Pratyush Srivastava;Koichi Tanaka;B. Ramirez;V. Gupta
中科院分区：
文献类型：
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作者：
Pratyush Srivastava;Koichi Tanaka;B. Ramirez;V. Gupta
高密度和超硬的硅镁石相是SiO2最稳定的形式。它是在熔融石英经受极端压力（>34 GPa）时形成的。在这篇文章中，我们报告了在7 GPa的非常低的压缩应力下，冲击加载的钠钙玻璃（SLG）样品中Stishovite相的成核。虽然它福尔斯落在2.5和7 GPa之间的SLG的报告Hugoniot弹性极限内，但它显著低于对熔融石英观察到的34 GPa的结晶阈值。SLG板冲击加载1-2.5 km/s使用桌面实验装置，其中产生直径1 mm的25-50 μm厚的Al微飞片，并使用8 ns持续时间的顶帽Nd：YAG激光脉冲推进。使用高分辨率透射电子显微镜（HRTEM）对冲击样品进行成像，并使用选区电子衍射和FFT分析进行进一步分析。所有样品均显示出分布在无定形SLG基质内的4 nm Stishovite晶体的成核。通过使用最先进的光子多普勒测速仪（PDV）直接测量飞片速度、颗粒速度和冲击波速度来确定应力状态。
Highly dense and ultra-hard Stishovite phase is the most stable form of SiO2. It is formed when fused silica is subjected to extreme pressures (>34 GPa). In this communication, we report nucleation of the Stishovite phase in shock-loaded soda-lime glass (SLG) samples at a remarkably low compressive stress of 7 GPa. Although it falls within the reported Hugoniot Elastic Limit of SLG between 2.5 and 7 GPa, it is significantly below the crystallization threshold of 34 GPa observed for fused silica. SLG plates were shock loaded by impacting them at 1–2.5 km/s using a table-top experimental setup in which 1 mm-dia Al micro flyer plates of 25–50 μm thickness were generated and propelled using a top-hat Nd:YAG laser pulse of 8 ns duration. The shocked samples were imaged using High Resolution Transmission Electron Microscopy (HRTEM) and further analyzed using Selected Area Electron Diffraction and FFT analyses. All samples showed nucleation of 4 nm Stishovite crystals distributed within the amorphous SLG matrix. The stress state was determined by directly measuring the flyer speed, particle velocity, and shockwave speed by using a state-of-the-art Photonic Doppler Velocimeter (PDV).