The Role of Crystallographic Defects in Ceramic Superplasticity

非技术描述：该项目研究如何故意引入材料中的缺陷（主要是线或边界处的原子错位），以使陶瓷材料在高温下具有延展性。 对于美国的陶瓷工业来说，潜在的经济节约是可能的，用于在高温下成形复合氧化物陶瓷部件，同时保持优异的室温机械性能。这项研究有助于培养研究生和本科生的多元化群体，并为将引入课程的材料中的晶粒边界和界面提供了新的研究生课程的基础。技术详细信息：除了通过设计新的超塑性陶瓷来促进超塑性成形的可能的商业应用之外，这项研究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。 首次确定莫来石的位错结构和滑移系，莫来石是一种因其优异的热稳定性、高抗热震性和低导热性而被提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.