压电材料中电致裂纹发射位错机理及其效应研究

项目名称： 压电材料中电致裂纹发射位错机理及其效应研究

项目编号： No.11202099

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 宋豪鹏

作者单位： 南京航空航天大学

项目金额： 28万元

中文摘要： 压电材料较差的韧性极大地限制了其应用范围。压电材料韧性差的根源之一在于其内部裂纹扩展所需的机械载荷低于位错发射所需的机械载荷，这导致一般情况下压电材料中的裂纹难以通过发射位错导致自身钝化并缓解裂尖的应力集中。本项目采用理论分析与实验观察测试相结合的方式，利用压电材料的力-电耦合特性，研究电载荷促使位错发射的机理和特征。通过研究压电材料中作用在位错上的各种力，建立压电材料中裂纹发射位错的模型和判据，讨论裂纹电可穿透性和几何形状、材料电弹常数、力电载荷配置、剩余位错在裂纹表面的分布及裂纹内部介电常数和电场等因素对位错发射和裂纹扩展的促进或抑制作用。探索促使压电材料中裂纹在扩展前发射位错并松弛应力的机理，为压电材料的增韧设计及断裂失效研究提供科学依据。

中文关键词： 压电材料；残余位错；位错发射；裂纹；增韧

英文摘要： The application of piezoelectric materials is severely limited by their poor toughness. One of the root causes of poor toughness of piezoelectric materials is that the mechanical load for crack propagation is lower than the mechanical load for dislocation emission. So cracks within piezoelectric materials can not blunt themselves and release the stress concentration through emit dislocations in ordinary circumstances. In this research project, by using of the electro-mechanical coupling characteristics of piezoelectric materials, the combination of theoretical analysis and experimental test is used to investigate the mechanism and characteristics of electrical loads to promote dislocation emission. By studying the forces acting on a dislocation in piezoelectric materials, building the model and criterion of cracks emit dislocations in piezoelectric materials, discussing the influence of electrical penetrability、electroelastic constants、Electro-mechanical load configuration、distribution of residual dislocation、dielectric constant and electric field within the crack on dislocation emission and crack propagation. Exploring the mechanism of promoting dislocation emission in piezoelectric material and provide scientific basis for piezoelectric material toughening design and fracture analysis.

英文关键词： piezoelectric materials；residual dislocation；dislocation emission；crack；toughened