The Role of Crystallographic Defects in Ceramic Superplasticity

非技术描述：这个项目研究如何故意引入材料中的缺陷(主要是线上或边界上未排列的原子)，使陶瓷材料在高温下具有延展性。对于美国的陶瓷行业来说，在高温下成型复合氧化物陶瓷部件，同时保持优异的室温机械性能，可能会节省潜在的经济成本。这项研究帮助培养了一批不同的研究生和本科生，并为将被引入课程的新的关于材料中的颗粒边界和界面的研究生课程提供了基础。技术细节：除了通过设计新的超塑性陶瓷来促进超塑性成形可能的商业应用之外，这项研究还将有助于理解莫来石和莫来石复合材料在高温下的基本变形机制。首次确定了莫来石的位错结构和滑移系统，莫来石具有优异的热稳定性、高抗热震性和低导热系数，是一种建议用于高温结构应用的材料。学生将接受高分辨率原子力显微镜(AFM)和聚焦离子束(FIB)仪器的先进技术培训，以研究相对晶界滑动和界面缺陷的作用。

NON-TECHNICAL DESCRIPTION: This project studies how defects in materials (primarily misaligned atoms in a line or at a boundary) can be deliberately introduced to make ceramic materials ductile at high temperatures. Potential economic savings are possible for the ceramics industry in the U.S. for use in shape-forming complex oxide ceramic components at high temperatures while retaining excellent room temperature mechanical properties. This research helps train a diverse cohort of graduate and undergraduate students and provides the basis for a new graduate course on Grain Boundaries and Interfaces in Materials that will be introduced into the curriculum. TECHNICAL DETAILS: In addition to promoting possible commercial applications of superplastic forming by designing new superplastic ceramics, this research will contribute to understanding the fundamental deformation mechanisms operative in mullite and mullite composites at high temperatures. For the first time the dislocation structure and slip system will be determined for mullite, a material proposed for use in high temperature structural applications due to its excellent thermal stability, high thermal shock resistance, and low thermal conductivity. Students will be trained in the advanced techniques of high resolution atomic force microscopy (AFM) and focused ion beam (FIB) instrumentation to study relative grain boundary sliding and the role of interfacial defects.