Time Dependent Creep Deformation of Non Polar Mixed Conducting Ferroelastic Perovskites

拟议的研究和教育项目集中于混合离子电子导电(MIEC)钙钛矿在室温和高温下的随时间变化的蠕变变形。由于目前还不能对钴酸镧、锰氧化物、铬铁矿、铁氧体和其他MIEC导体的蠕变起源有基本的了解，我们建议研究蠕变作为外部载荷、加载速度、时间、温度、磁场壁迁移率以及材料组成、晶体结构和晶粒度的函数。实验和模型研究都是为了研究随时间变化的蠕变变形机制，确定导致这种现象的驱动力，并开发新的策略，使MIEC钙钛矿中随时间变化的变形的影响降到最低。对MIEC钙钛矿中随时间变化的蠕变的基本了解对于进一步成功开发高可靠性和高精度的器件，如传感器和执行器，或需要线性的、与时间无关的机械输出的不同的电化学器件具有重要意义。本研究计划为机械和材料工程专业的学生积极参与基于项目的学习提供了理想的基础。综合研究和教育活动包括接触不同的高中生群体和为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，并将指导本科生和高中生研究人员。将特别努力通过高中外展和本科生研究来吸引代表性不足的学生在材料科学和工程领域从事职业生涯。

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.