Micromechanics simulation of spontaneous polarization in ferroelectric crystals
Micromechanics simulation of spontaneous polarization in ferroelectric crystals
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DOI：
10.1063/1.1388567
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发表时间：
2001-08
影响因子：
3.2
通讯作者：
Wenfang Li;G. Weng
中科院分区：
文献类型：
--
作者：
Wenfang Li;G. Weng
基于改进的等效夹杂法和热力学理论，开发了一个微观力学模型来预测单晶铁电陶瓷冷却时内应力的演变以及微观结构特征（即新畴浓度和孔隙率）和外部静水压力对转变温度的影响。在立方体到四方体的转变过程中，材料是一种复合材料，由于相变而具有内应力。考虑热力学驱动力和阻力，得出一个动力学方程，该方程提供了给定温度和施加应力水平下新域的体积浓度。这种新的畴浓度导致整体电极化的增加。利用 BaTiO3 特性进行的数值计算表明，自发极化过程中母体立方相的内应力继续发展，而孔隙率的增加极大地促进了转变过程。
Based on a modified equivalent inclusion method and a thermodynamic theory, a micromechanics model is developed to predict the evolution of internal stress and the effects of microstructural features (i.e., new domain concentration and porosity) and the external hydrostatic pressure on the transition temperature for single crystal ferroelectric ceramics upon cooling. During the cubic-to-tetragonal transition the material is a composite, with an internal stress due to phase transformation. Consideration of the thermodynamic driving force and resistance force leads to a kinetic equation that provides the volume concentration of new domains at a given level of temperature and applied stress. This new domain concentration results in an increase of overall electric polarization. Numerical calculations using the properties of BaTiO3 indicate that internal stress in the parent cubic phase continues to develop during spontaneous polarization, and that increased porosity greatly facilitates the transition process....