International Research Fellowship Program: Device Reliability and Fracture of Electroceramics

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0402066JonesThe International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-two month research fellowship by Dr. Jacob L. Jones to work with Dr. Mark Hoffman at the University of New South Wales in Sydney, Australia for 12 months, and Dr. Ersan Ustundag at Iowa State University for 10 months.Ferroelectric materials couple electrical and mechanical energy, making them ideal for active components in actuators, sensors and transducers in applications including medical ultrasonic imaging, piezoelectric buzzers, ultrasonic motors, sonar, and high-precision measurement systems. In medical and other sophisticated applications, failure of the ferroelectric device, particularly by fracture, is unacceptable. This research quantifies the role of microstructure in crack initiation, propagation and failure of cyclically loaded ferroelectric devices, leading ultimately to enhanced reliability. Damage initiation including subsurface microcracking and change in fracture toughness as a function of crack extension (R-curve) is observed and characterized using techniques offered by Dr. Hoffman. Microstructural parameters including strain, texture and composition are quantified in situ during crack propagation experiments using novel diffraction technologies applied extensively in Dr. Ustundag's research. The results from these experiments are combined to develop a model for damage evolution in ferroelectric and ferroelastic materials