Mechanically induced ferroelectric domain evolution during crack propagation
Mechanically induced ferroelectric domain evolution during crack propagation
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DOI：
10.1088/1361-665x/aaf67d
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发表时间：
2019-01
影响因子：
4.1
通讯作者：
S. Kozinov;M. Kuna
中科院分区：
文献类型：
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作者：
S. Kozinov;M. Kuna
锆钛酸铅陶瓷裂纹尖端的铁电反转导致极化和残余应变的变化，从而对应力场和断裂行为产生重要影响。特别地，对于四元晶体，90°畴重取向被认为提高了受损压电陶瓷的断裂韧性。目前的研究模型在裂纹扩展过程中的域重取向过程的演变的微观力学模型，使用有限元分析。裂纹扩展的数值模拟是通过沿预期裂纹路径沿着的机电内聚单元来实现的，这些不可逆耗散机制的研究是我们数值研究的主要内容。将机械加载的PZT-PIC 151 CT试样中的畴取向的计算的3D散射与同步加速器中的原位X射线衍射实验进行比较（Jones等人2007 Acta Mater. 55，5538-5548）。结果表明，机械加载试样中畴分布的择优取向和强度依赖于面内位置，并与投影偏应力/应变有关。与具有固定裂纹尖端的模拟相反（Kozinov和Kuna 2018 Arch. Appl. Mech.），在裂纹扩展过程中，最大拉伸应力和畴重取向的最高强度区域随裂纹尖端移动，并在处理区域上被涂抹。随着裂纹长度的增加，畴转换带产生屏蔽效应，导致材料明显增韧。这种完全耦合的，三维模拟裂纹扩展阻力曲线是第一个在铁电体。
Ferroelectric switching near the crack tip in lead zirconate titanate ceramics leads to a change of both polarization and remanent strain, which affects substantially the stress field and fracture behavior. In particular, for tetragonal crystals the 90° domain reorientation is believed to enhance fracture toughness of the damaged piezoelectric ceramics. Current research models evolution of the domain reorientation processes during crack propagation by a micromechanical model using finite element analysis. The crack growth is numerically simulated by means of electromechanical cohesive elements along the prospective crack path. The study of these irreversible dissipative mechanisms makes the main subject of our numerical investigations. The computed 3D scattering of domain orientations in a mechanically loaded PZT-PIC151 CT-specimen is compared with in situ x-ray diffraction experiments in synchrotron (Jones et al 2007 Acta Mater. 55, 5538–5548). It is found that the preferred orientation and intensity of domain distribution in the mechanically loaded specimen depend on the in-plane position and are related to the projected deviatoric stresses/strains. In contrast to simulations with a fixed crack tip (Kozinov and Kuna 2018 Arch. Appl. Mech.), during crack propagation the maximal tensile stresses and region of highest intensity of domain reorientation are moved with the crack tip and smeared over a process zone. While the crack length increases, the domain switching belt causes a shielding effect leading to an apparent materials toughening. Such fully coupled, three-dimensional simulation of crack growth resistance curves is the first one in ferroelectrics.