CAREER: Time-Resolved Structure-Property Relationships in Piezoelectric Ceramics

非技术描述：压电陶瓷可以耦合电能和机械能，使我们能够以多种方式感知环境并与之互动。利用压电陶瓷的设备的例子包括诊断和治疗超声、声纳、振动和位置传感、大位移驱动、包括微定位在内的微技术以及可再生发电或能量收集。这些应用中的许多通常在动态条件下工作，虽然目前可以在这些条件下测量材料的性能，但还不存在能够表征动态加载期间材料的结构状态作为时间的函数的时间分辨结构表征技术。该计划将使用本地仪器和国际同步辐射衍射设备开发时间分辨X射线衍射技术，并应用这些工具来发展对压电陶瓷随时间变化的结构行为的更基本的理解。这一程序将导致一种全新的方法来协调宏观性质方面的结构动力学在时间和频率域，并已在许多其他材料系统的应用。在压电陶瓷领域，这一框架将促进无铅、高温和多铁性传感器和执行器的发展。该计划的一个主要教育组成部分是发展国际伙伴关系，并为学生提供国际研究经验。该项目将使学生能够在欧洲一流的研究机构进行实践研究。这些经历将培养人们对文化和教育背景、经验和智力方法的多样性的认识和欣赏。这项建议的另一个重要教育组成部分是为佛罗里达大学的时间分辨结构研究开发内部仪器。在多用户设施中开发内部仪器将加强区域研究和教育基础设施，并促进下一代仪器的开发和传播。将为内部仪器开发动手模块，以帮助教授本科生陶瓷实验室、核心和专业本科生课程以及研究生课程。还将开发和传播对衍射数据集进行系统和一致分析的通用软件工具。技术细节：材料科学家经常通过结构-性质关系从微观来源的角度描述材料的宏观行为。对于在动态扰动下测量的宏观性质，由于缺乏时间分辨的结构表征技术，这种联系的开发尤其困难。该计划的主要目标是建立一个新的框架，在这个框架内研究压电陶瓷的结构和宏观性能之间的关系。这将通过开发大块压电陶瓷X射线衍射过程中的时间分辨频闪数据收集技术来实现。所建立的框架将被用来增强对各种压电陶瓷系统中的滞后、非线性和频率色散的基本理解。例如，时间分辨技术将能够定量确定外部机制，如磁区壁和相间边界运动对宏观性质的作用。最终，这将导致对多晶压电陶瓷宏观机电行为的起源及其频率和时间相关性的更好的理解。在整个项目过程中，学生们将前往欧洲同步辐射设施和洛桑联邦理工学院，与领先的科学家合作，同时进行高能X射线衍射实验和互补性质测量。

NON-TECHNICAL DESCRIPTION: Piezoelectric ceramics can couple electrical and mechanical energy, enabling us to sense and interact with our environment in multiple ways. Examples of devices utilizing piezoelectric ceramics include diagnostic and therapeutic ultrasound, sonar, vibration and position sensing, large-displacement actuation, micro-technologies including micro-positioning, and renewable power generation or energy harvesting. Many of these applications often function under dynamic conditions and although material properties can currently be measured under these conditions, time-resolved structural characterization techniques do not yet exist that can characterize the structural state of materials as a function of time during dynamic loading. This program will develop time-resolved X-ray diffraction techniques using both local instrumentation and through access to international synchrotron diffraction facilities and apply these tools to develop a more fundamental understanding of the time-dependent structural behavior of piezoelectric ceramics. This program will lead to an entirely new way of reconciling macroscopic properties in terms of structural dynamics in the time and frequency domains and has application in numerous other material systems. In piezoelectric ceramics, this framework will promote the development of lead-free, high-temperature, and multiferroic sensors and actuators. A primary educational component of this program is the development of international partnerships and the provision of international research experiences for students. This program will enable students to perform hands-on research at top-tier research institutions in Europe. These experiences will foster an awareness and appreciation for diversity of cultural and educational background, experience, and intellectual approach. Another significant educational component of this proposal is the development of in-house instrumentation for time-resolved structural studies at the University of Florida. The development of in-house instrumentation in a multi-user facility will enhance regional infrastructure for research and education and promote the development and dissemination of next-generation instrumentation. Hands-on modules will be developed for the in-house instrumentation to help teach undergraduate ceramics laboratories, core and specialty undergraduate courses, and graduate courses. Versatile software tools for the systematic and consistent analysis of diffraction datasets will also be developed and disseminated. TECHNICAL DETAILS: Materials scientists often describe the macroscopic behavior of materials in terms of microscopic origins through structure-property relationships. For macroscopic properties measured under dynamic perturbation, the development of such linkages is particularly difficult due to the lack of time-resolved structural characterization techniques. The primary goal of this program is to establish a new framework in which to investigate the relationship between structure and macroscopic properties of piezoelectric ceramics in the time domain. This will be accomplished by developing time-resolved stroboscopic data collection techniques during X-ray diffraction of bulk piezoelectric ceramics. The established framework will then be used to enhance the fundamental understanding of hysteresis, nonlinearity, and frequency dispersion in a variety of piezoelectric ceramic systems. For example, time-resolved techniques will enable a quantitative determination of the role of extrinsic mechanisms such as domain wall and interphase boundary motion on macroscopic properties. Ultimately, this will lead to an enhanced understanding of the origin of the macroscopic electromechanical behavior and its frequency and time dependence in polycrystalline piezoelectric ceramics. Throughout the course of the program, students will travel to the European Synchrotron Radiation Facility and the Ecole Polytechnique Federale de Lausanne to work with leading scientists while conducting high-energy X-ray diffraction experiments and complementary property measurements.