PZT压电陶瓷缺陷偶极子诱导的电致应变效应及相关物理机制研究

近年来，基于点缺陷短程有序对称一致性原理、由缺陷偶极子诱导的巨可逆电致应变效应日益受到广泛关注。目前关于压电材料获得高可逆电致应变的微观结构调控机制尚不清晰，大应变获得存在不确定性。准同型相界（MPB）附近PZT压电陶瓷存在多尺度畴结构，引入缺陷偶极子时，材料中极性结构之间相互作用以及对外场响应更加复杂。本项目在前期研究基础上，以MPB附近PZT基压电陶瓷为研究对象，从调控缺陷偶极子和铁电畴状态本质出发，通过改变组成、晶粒尺寸、加载历史，研究不同组成和制备工艺对电致应变特性的影响规律；揭示缺陷偶极子与多尺度铁电畴结构调控机制; 研究外场下缺陷偶极子和铁电畴响应行为以及对电致应变特性的影响，建立宏观电致应变与微观结构的内在联系，发展出获得高电致应变和稳定应变记忆效应的新方法。本项目的实施将深化对与缺陷偶极子相关的电致应变效应的理解，为设计高性能新材料、拓展压电材料新应用提供科学依据和指导。

Recently, based on symmetry-conforming principle for point defect, the large recoverable electrostrain effect induced by defect dipole have widely been paid attention. However, the microstructure regulation mechanism of high recoverable electrostrain is not clear, and the induced high recoverable electrostrain is uncertain. PZT piezoelectric ceramics close to the morphotropic phase boundary (MPB) have multi-scale domain structures. The interaction between these polarities and their response to external field are much complicated. Based on our earlier research results, we propose an novel idea to control the status of defect dipole and ferroelectric domain by changing the composition, the grain size and the post process method. The influence of composition and process on the electrostrain properties will be studied, and the structure regulation mechanisms of defect dipole and ferroelectric domain will be revealed. The defect dipole and the domain response to external field and their affect on the electrostrain will be investigated. The purpose of this project is to establish the relationship between the macroscopic electrostrain property and microscopic physics mechanism, and to develop the novel way to obtain the large recoverable electrostrain and strain memory effect. This project will promote the understanding about the electrostrain induced by defect dipoles. Moreover, these achievements could provide scientific directions and references for the development of novel devices as potential candidate for future applications.