Time Dependent Creep Deformation of Non Polar Mixed Conducting Ferroelastic Perovskites

提出的研究和教育项目侧重于混合离子电子导电（MIEC）钙钛矿在室温和高温下随时间的蠕变变形。由于对钴酸镧、锰酸盐、铬铁矿、铁氧体和其他MIEC导体的时间相关蠕变的起源还没有基本的了解，我们建议研究蠕变作为外部载荷、加载速率、时间、温度、畴壁迁移率以及材料成分、晶体结构和晶粒尺寸的函数。本文提出了实验和模型研究，以研究时间相关蠕变的机制，确定导致这种现象的驱动力，并制定新的策略，以最大限度地减少MIEC钙钛矿中时间相关变形的影响。对MIEC钙钛矿中时间相关蠕变的基本理解对于进一步成功开发高度可靠和精确的设备（如传感器和执行器）或不同的电化学设备（需要线性，时间无关的机械输出）具有重要意义。本研究项目为机械与材料工程专业学生积极参与项目学习提供了理想的基础。综合研究和教育活动包括向不同群体的高中生和本科生提供研究机会。研究生将参与研究，在技术会议上发表演讲，并指导本科生和高中生研究人员。将特别努力吸引代表性不足的学生通过高中外展和本科研究来追求材料科学和工程方面的职业。

The proposed research and educational project focuses on time dependent creep deformation of mixed ionic electronic conducting (MIEC) perovskites at room and elevated temperatures. Because a basic understanding of the origin of the time dependent creep is not currently available for lanthanum cobaltites, manganites, chromites, ferrites, and other MIEC conductors, we propose to study creep as a function of external load, loading rate, time, temperature, domain wall mobility, as well as materials composition, crystal structure and grain size. Both experimental and modeling research is proposed to study the mechanisms of time dependent creep deformations, to define driving forces responsible for the phenomena, and to develop new strategies that will allow minimizing the effect of time dependent deformation in MIEC perovskites. A fundamental understanding of time dependent creep in MIEC perovskites is of major importance for further successful development of highly reliable and precise devices such as sensors and actuators, or different electrochemical devices where linear, time independent mechanical output is desirable.The present research program provides an ideal basis for Mechanical and Materials Engineering students to actively participate in project-based learning. Integrated research and educational activities include outreach to a diverse group of high school students and research opportunities for undergraduate students. Graduate students will be involved in research, presentations at technical meetings, and will mentor undergraduate and high school student researchers. Special efforts will be made to attract underrepresented students to pursue their careers in materials science and engineering through high school outreach and undergraduate research.