Femtosecond X-Ray Diffraction Studies of Crystalline Matter Deforming under Extreme Loading

极端载荷下晶体物质变形的飞秒 X 射线衍射研究

• 批准号: EP/X031624/1
• 负责人: Justin Wark
• 金额: $ 63.41万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FX031624%2F1
• 关键词: Femtosecond; Ray; Diffraction; Studies; Crystalline

X-ray free-electron lasers (XFELs) are the most brilliant sources of x-rays on Earth. The highly coherent, near-monochromatic, sub-picosecond bursts of radiation they deliver make them the ultimate 'high-speed camera', capable of capturing extremely fast, atomic-level phenomena as they unfold in unprecedented detail. XFELs are therefore ideally suited to probing matter undergoing laser-based dynamic compression, whereby one or more high-power optical lasers rapidly vaporise the surface of a solid target, launching into it a compression wave that generates internal stresses many millions of times greater than atmospheric pressure. During the few billionths of a second for which they survive before being disintegrated, these targets reach extreme pressures of the kind ordinarily encountered only in planetary interiors, and experience rates of deformation rivalling those of meteoric impact events. By illuminating these short-lived samples with extremely bright XFEL pulses, we can generate x-ray diffraction or absorption spectra rich with information about their atomic arrangement, structure, and dynamics in the moments before their destruction. This ability to diagnose the dynamic response of matter under extraordinary thermodynamic conditions is transforming experimental high-pressure physics, allowing us to better understand not only the internal structure, formation, and collision dynamics of planetary bodies, but how to synthesise and recover exotic high-pressure phases of matter, and how engineering alloys and ceramics respond to the huge dynamic stresses created by hypervelocity impacts.In this project, we aim to leverage the diagnostic power of the recently commissioned European XFEL (EuXFEL), an international XFEL facility backed by a consortium of twelve countries to which the UK has committed approximately £30M in capital to date. We will exploit the EuXFEL to shed new light on the plasticity and strength of model metals dynamically deforming at extreme pressures and strain rates. Our aim is to take the 'ordinary' physical processes controlling plastic deformation that materials scientists have studied for over a century, and to examine them under the 'extraordinary' thermodynamic conditions accessible via dynamic compression. Using the UK-built, high-repetition-rate, £8M DiPOLE-100 laser recently installed at EuXFEL, we will laser-compress a range of metals and alloys to planetary pressures over nanosecond timescales at an unprecedented shot rate. We will use femtosecond x-ray diffraction to measure the ultrafast rotation experienced by our samples' microstructure, and use it to identify the plasticity mechanisms that relieve the colossal shear stresses accumulated during compression. From these same diffraction measurements, we will extract the strain state of our metallic samples, allowing us to measure their dynamic strength at extreme strain rates. We will also use EuXFEL to study these samples' x-ray absorption properties under extreme loading, with which we can track their temperature dynamics in situ. Together, these XFEL-enabled experimental measurements of plasticity mechanisms, strength, and temperature evolution have the potential to transform our understanding of material deformation physics under extreme loading conditions.

X射线自由电子激光器（XFELS）是地球上X射线最出色的来源。它们传递的高度连贯，近乎单色的，次秒的辐射爆发使它们成为最终的“高速摄像机”，能够以前所未有的细节捕获它们非常快，原子级现象。因此，Xfels非常适合进行基于激光的动态压缩的探测物质，因此一个或多个高功率光激光器迅速使固体靶标表面迅速蒸发，从而引发了一个压缩波，从而产生了内部应力，比大气压大了数百万倍。在它们在瓦解之前生存的几十亿分之一的时间里，这些目标通常达到了通常仅在行星室内遇到的极端压力，并且经验的变形率逐渐使陨石冲击事件的变形效果。通过用极明亮的XFEL脉冲照亮这些短寿命的样品，我们可以在破坏之前的那一刻产生有关其原子布置，结构和动态的信息丰富的X射线衍射或遭受痛苦的光谱。 This ability to diagnose the dynamic response of matter under extraordinary thermodynamic conditions is transforming experimental high-pressure physics, allowing us to better understand not only the internal structure, formation, and collision dynamics of planetary bodies, but how to Synthesis and recover exotic high-pressure phases of matter, and how engineering alloys and ceramics respond to the huge dynamic stresses created by hypervelocity impacts.In this project, we aim to leverage the diagnostic最近委托的欧洲XFEL（EUXFEL）的权力，这是一家国际XFEL设施，由十二个国家的财团支持，英国迄今已承诺了大约3000万英镑的资本。我们将利用Euxfel，以使模型金属的可塑性和强度在极端压力和应变速率下动态变形。我们的目的是采用控制材料科学家研究了一个多世纪的塑性变形的“普通”物理过程，并在可以通过动态压缩的“非凡”热力学条件下检查它们。使用最近在Euxfel安装的英国建造的高度重复率，800万英镑的偶极100偶极激光，我们将以前所未有的射击率激光压缩一系列金属和合金到纳米秒时标准的行星压力。我们将使用飞秒X射线衍射来通过样品的微观结构来测量超快旋转体验，并使用它来识别减轻压缩过程中巨大剪切应力的可塑性机制。通过这些相同的衍射测量值，我们将提取金属样品的应变状态，从而使我们能够在极端应变速率下测量其动态强度。我们还将使用Euxfel在极端负载下研究这些样品的X射线抽象特性，我们可以在其原位跟踪它们的温度动态。共同，这些支持XFEL的实验测量可塑性机制，强度和温度演化有可能改变我们对极端负荷条件下材料变形物理学的理解。