Center for High Pressure Science and Technology Advanced Research, Beijing 100094, P. R. China.
Center for Excellence in Deep Earth Science, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, P. R. China.
Proc Natl Acad Sci U S A. 2021 Dec 21;118(51). doi: 10.1073/pnas.2118490118.
Diamond is the hardest known material in nature and features a wide spectrum of industrial and scientific applications. The key to diamond's outstanding properties is its elasticity, which is associated with its exceptional hardness, shear strength, and incompressibility. Despite many theoretical works, direct measurements of elastic properties are limited to only ∼1.4 kilobar (kb) pressure. Here, we report ultrasonic interferometry measurements of elasticity of void-free diamond powder in a multianvil press from 1 atmosphere up to 12.1 gigapascal (GPa). We obtained high-accuracy bulk modulus of diamond as = 439.2(9) GPa, ' = 3.6(1), and shear modulus as = 533(3) GPa, ' = 2.3(3), which are consistent with our first-principles simulation. In contrast to the previous experiment of isothermal equation of state, the ' obtained in this work is evidently greater, indicating that the diamond is not fully described by the "-" Mie-Grüneisen model. The structural and elastic properties measured in this work may provide a robust primary pressure scale in extensive pressure ranges.
钻石是自然界中已知的最硬物质，具有广泛的工业和科学应用。钻石卓越性能的关键在于其弹性，这与其极高的硬度、剪切强度和不可压缩性有关。尽管有许多理论工作，但对弹性性能的直接测量仅限于约 1.4 千巴（kb）的压力。在这里，我们报告了在多砧压机中对无空洞金刚石粉末弹性的超声干涉测量，压力范围从 1 大气压到 121 吉帕斯卡（GPa）。我们得到了金刚石的高精度体弹模量 = 439.2(9) GPa，' = 3.6(1)，剪切模量 = 533(3) GPa，' = 2.3(3)，与我们的第一性原理模拟结果一致。与以前的等温状态方程实验相比，本工作中得到的 '明显更大，表明金刚石不能完全用 "-" Mie-Grüneisen 模型来描述。本工作测量的结构和弹性性质可能为广泛的压力范围内提供一个稳健的初始压力标度。
