MSE Seminar: Xiaoqin Ke, Simulation of Interdiffusion Microstructures

Abstract

Phase field method is a powerful tool to simulate microstructure evolution and is widely used in nearly all fields of materials science. In this work, we apply phase field methods coupled with thermodynamic models to simulate both interdiffusion microstructures of high temperature coatings and domain structure/piezoelectric property at ferroelectric morphotropic phase boundary. For interdiffusion microstructures of high temperature coatings, a special interdiffusion microstructure containing n phases changing across the interphase boundary in n-component systems (type n boundaries) are obtained by simulations and are comparable to experimental observations. Also, the fundamentals of interdiffusion microstructure maps which should be useful for coating design are explored. For ferroelectric morphotropic phase boundary (MPB) which possess the best piezoelectric property, the simulated hierarchical domain within domain structure at MPB exhibits striking similarity with experimental observed ones and the phase of these nanodomains is found to be the newly discovered monoclinic phase and the reason why monoclinic phase forms at MPB is explored. Also, the piezoelectric property of ferroelectric MPB is studied and the origin of good piezoelectric property at the MPB is explored. These two examples demonstrate clearly that the application of phase field methods coupled with appropriate thermodynamic models can predict the microstructure of important material systems and can assist in the understanding of composition-microstructure-property relations.

Bio

Xiaoqin graduated in 2007 from Xi’an Jiaotong Univeristy of China with a bachelor’s degree in life science and technology. She got a master degree from Xi’an Jiaotong University in 2009 in materials science and engineering. Since 2009, she has been pursuing a Ph.D. in Materials Science and Engineering at the Ohio State University under the supervision of Prof. Yunzhi Wang. Her research mainly focuses on interdiffusion microstructure of high temperature coatings and domain structure/piezoelectric property of ferroelectric materials.