Three tungsten powder samples—one coarse grained (c-W; grain size: 1 µm–3 µm) and two nanocrystalline (n-W; average grain sizes: 10 nm and 50 nm)—are investigated under nonhydrostatic compression in a diamond anvil cell in separate experiments, and their in situ X-ray diffraction patterns are recorded. The maximum microscopic deviatoric stress in each tungsten sample, a measure of the yield strength, is determined by analyzing the diffraction line width. Over the entire pressure range, the strength of tungsten increases noticeably as the grain size is decreased from 1 µm–3 µm to 10 nm. The results show that the yield strength of tungsten with an average crystal size of 10 nm is around 3.5 times that of the sample with a grain size of 1 µm–3 µm.

中文翻译：

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纳米晶钨在高压下的强度增强

三个钨粉样品——一个粗晶粒（cW；晶粒尺寸：1 µm–3 µm）和两个纳米晶体（nW；平均晶粒尺寸：10 nm 和 50 nm）——在不同的实验中在金刚石砧座中的非流体静力压缩下进行研究，并记录了它们的原位 X 射线衍射图。每个钨样品中的最大微观偏应力，屈服强度的量度，是通过分析衍射线宽度确定的。在整个压力范围内，随着晶粒尺寸从 1 µm–3 µm 减小到 10 nm，钨的强度显着增加。结果表明，平均晶体尺寸为 10 nm 的钨的屈服强度是晶粒尺寸为 1 µm–3 µm 样品的屈服强度的 3.5 倍左右。