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

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

0129025 Lynch This 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.