U.S.-Germany Cooperative Research: Rate Effects in the Fracture Toughness of Ferroelectric Ceramics under Mechanical Loading

该奖项支持Christopher Lynch和佐治亚理工学院的学生与德国达姆施塔特工业大学材料系的Juergen Roedel合作。这个国际项目的目的是设计出比目前使用的铁电陶瓷更不脆、更可靠的铁电陶瓷。这将需要详细了解在电气和机械载荷下的准静态和疲劳裂纹特性。为了提高材料的性能，必须充分了解其失效机制。这个美国小组开发了一种有限元计算机代码，能够确定铁电材料中的应力和电场浓度。德国团队开发了实验技术和专用夹具，用于测量脆性材料在电气和机械联合载荷下的裂纹扩展行为。通过结合两组的优势，新的分析技术和新的实验技术将有可能全面了解锆钛酸铅（PZT）的断裂过程，从而阐明微观结构在断裂过程中的作用。工作计划规定研究生广泛参与国际旅行和研究。

0129025LynchThis award supports Christopher Lynch and students from Georgia Tech in a collaboration with Juergen Roedel of the Department of Material at the Technical University of Darmstadt, Germany. The aim of the international project is to design ferroelectric ceramics that are less brittle and more reliable than those used today. This will require detailed knowledge of both the quasi-static and fatigue crack properties under both electrical and mechanical loading. To improve the materials properties, the mechanisms of their failure have to be fully understood. The US group has developed a finite element computer code capable of determining stress and electric field concentrations in ferroelectric materials. The German group has developed experimental techniques and specialized fixtures for measuring the crack propagation behavior of brittle materials under combined electrical and mechanical loading. By bringing together the strengths of both groups, new analytical techniques and new experimental techniques will make possible a full understanding of the fracture process in lead zirconate titanate (PZT), which in turn will elucidate the role of microstructure in the fracture process. The work plan provides for extensive participation by graduate students in the international travel and research.