0


用原位X射线和中子衍射确定机电应变的成因

Origins of Electromechanical Strain Ascertained from in situ X-ray and Neutron Diffraction
课程网址: http://videolectures.net/kolokviji_jones_neutron_diffraction/  
主讲教师: Jacob L. Jones
开课单位: 北卡罗来纳州立大学
开课时间: 2015-02-03
课程语种: 英语
中文简介:
电介质和压电材料用于储存和转换电能和机械能,使它们成为广泛应用和装置的必要条件,包括冲击和位移传感器、致动器、电容器、微电子机械系统、柴油机喷油器、声纳和超声波。在这些应用中,介电系数和压电系数决定了器件的性能和工作极限。然而,材料响应的真正起源,以及由此而来的特性系数,由于对这些特性(例如,离子和偶极极化率、铁弹性畴壁运动、相间边界运动等)的大量复杂的微观结构和晶体学贡献,还没有很好地理解,本征压电效应等)。这篇演讲将展示我们使用先进的原位X射线和中子散射方法来识别这些电活性材料的基本力学和物理性质,最终揭示这些不同机制对性能系数的贡献。在所有情况下,直接测量晶格变形(如压电)和晶内界面(例如畴壁、界面)运动的贡献,都与基于微观力学的公式的特性系数定量相关。
课程简介: Dielectric and piezoelectric materials are used to store and convert electrical and mechanical energy, making them essential to a broad range of applications and devices including impact and displacement sensors, actuators, capacitors, microelectromechanical systems, diesel fuel injectors, sonar, and ultrasound. In these applications, the dielectric and piezoelectric coefficients define the performance and the limits of device operation. However, the true origin of the material response, and thus the property coefficients, are not well understood because of the numerous and complex microstructural and crystallographic contributions to these properties (e.g., ionic and dipolar polarizability, ferroelastic domain wall motion, interphase boundary motion, the intrinsic piezoelectric effect, etc.). This talk will demonstrate our use of advanced in situ X-ray and neutron scattering methods to discern the underlying mechanics and physics at play in these electro-active materials, ultimately revealing the contribution of these various mechanisms to the property coefficients. In all cases, direct measurements of the contribution from lattice deformation (e.g., piezoelectric) and the motion of intragranular interfaces (e.g., domain walls, interphase boundaries) are quantitatively related to the property coefficients using micromechanics-based formulations.
关 键 词: 机电应变; X射线; 中子衍射
课程来源: 视频讲座网
数据采集: 2020-11-26:yxd
最后编审: 2020-11-26:yxd
阅读次数: 32