Conducting crack propagation driven by electric fields in ferroelectric ceramics
Conducting crack propagation driven by electric fields in ferroelectric ceramics
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DOI：
10.1016/j.actamat.2013.07.050
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发表时间：
2013-11
期刊：
影响因子：
9.4
通讯作者：
A. Abdollahi;I. Arias
中科院分区：
文献类型：
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作者：
A. Abdollahi;I. Arias
铁电陶瓷在高电场作用下容易断裂，高电场通常产生于电极或导电层附近。在本工作中，我们将铁电单晶断裂的相场模型推广到纯电载荷下导电裂纹扩展的模拟中。这是通过将扩散导电层的电焓引入相场公式来实现的。模拟结果表明，在正、负电场作用下，铁电试样中裂纹呈斜向扩展，裂纹从导电缺口向外分支，形成树形裂纹。显微组织演化表明，裂纹形成了尾对尾和头对头的90°区域，导致裂纹周围电荷积聚。电荷积累，反过来，诱导一个高电场，从而产生高静电能，进一步推动导电裂纹。并与实验结果进行了比较。
Ferroelectric ceramics are susceptible to fracture under high electric fields, which are commonly generated in the vicinity of electrodes or conducting layers. In the present work, we extend a phase-field model of fracture in ferroelectric single crystals to the simulation of the propagation of conducting cracks under purely electrical loading. This is done by introducing the electrical enthalpy of a diffuse conducting layer into the phase-field formulation. Simulation results show oblique crack propagation and crack branching from a conducting notch, forming a tree-like crack pattern in a ferroelectric sample under positive and negative electric fields. Microstructure evolution indicates the formation of tail-to-tail and head-to-head 90° domains, which results in charge accumulation around the crack. The charge accumulation, in turn, induces a high electric field and hence a high electrostatic energy, further driving the conducting crack. Salient features of the results are compared with experiments.