Ferroelectric materials are widely used in our daily life and many advanced industrial products. The understanding of their fracture behavior has been in the focus of research for decades, since the success of their application requires reliability and durability. For ferroelectric fracture behavior, different fracture criteria have been proposed and the influence of various mechanical-electric loading combinations on crack propagation have been investigated. However, the crack path and the deflection of crack propagation in ferroelectrics are still not satisfactorily understood. In this work, a three-point bending test for specimens of polarized PZT-5H with off-center notches is set up. Besides a pure mechanical loading, positive and negative electric fields below the coercive field are applied. Since the initial crack is not aligned with the mechanical loading axis, the crack does not propagate straightforwardly. A variety of crack paths are compared and statistically evaluated, illuminating the influence of electric loading. Recordings with a high-speed camera reveal unexpected details of crack initiation and growth. A modified J-integral vector criterion considering just the mechanical part of the driving force is proposed for numerical analyses of crack paths in piezoelectrics. The results of simulations based on this and other deflection criteria are finally compared to the experimental findings.

铁电材料广泛应用于我们的日常生活和许多先进的工业产品中。由于成功应用其可靠性和耐用性，对断裂行为的理解一直是研究的重点。对于铁电断裂行为，已经提出了不同的断裂准则，并研究了各种机电载荷组合对裂纹扩展的影响。然而，铁电体中的裂纹路径和裂纹扩展的偏转仍不能令人满意。在这项工作中，建立了偏心缺口偏光PZT-5H标本的三点弯曲测试。除了纯机械负载外，还施加矫顽力以下的正负电场。由于初始裂纹未与机械载荷轴对齐，因此裂纹不会直接传播。比较了各种裂纹路径并进行了统计评估，从而阐明了电负载的影响。使用高速摄像机进行的记录揭示了裂纹萌生和扩展的意外细节。修改后的提出了仅考虑驱动力机械部分的J积分矢量准则，用于压电裂纹路径的数值分析。最后将基于此变形标准和其他变形标准的模拟结果与实验结果进行比较。