Fatigue crack growth in ferroelectric ceramics driven by alternating electric fields
Fatigue crack growth in ferroelectric ceramics driven by alternating electric fields
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DOI：
10.1111/j.1551-2916.2004.00840.x
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发表时间：
2004-05
影响因子：
3.9
通讯作者：
D. Fang;B. Liu;Chin Teh Sun
中科院分区：
文献类型：
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作者：
D. Fang;B. Liu;Chin Teh Sun
研究了含裂纹PZT-5铁电陶瓷的电场诱导疲劳裂纹扩展。实验结果表明，电载荷作用下裂纹扩展有两个明显的特征。在低电负荷下，位于主裂纹前方的微裂纹出现并扩展，从而阻碍了主裂纹的扩展。而在高电载荷下，微裂纹消失，主裂纹是疲劳裂纹的唯一形式。宏观上主裂纹沿垂直于电场方向的原始路径沿着扩展。微观上，裂纹沿着晶界扩展，并观察到晶粒断裂。裂纹扩展速率与循环电载荷呈非线性关系。与机械疲劳相似，在外加电场幅值范围内存在裂纹扩展阈值，低于此阈值裂纹停止扩展。当外加电场超过这个阈值时，裂纹会稳定地扩展。得到了裂纹扩展的经验模型。用畴变效应和断裂力学的概念解释了电载荷作用下裂纹闭合和扩展的现象。
Electric-field-induced fatigue crack growth in ferroelectric ceramic PZT-5 with precracks was investigated. The experimental results showed that there were two distinct characteristics in the crack growth under electric loading. Under low electric loads, microcracks located ahead of the main crack emerged and grew and, as a result, impeded the growth of the main crack. On the other hand, under high electric loads, microcracks were absent, and the main crack was the only mode of fatigue cracking. The main crack grew macroscopically along the original path perpendicular to the electric field. Microscopically, the crack grew along the grain boundaries and grain breakaway was observed. The crack growth rate was nonlinearly related to the cyclic electric load. Similar to mechanical fatigue, there existed a crack growth threshold in the applied electric-field amplitude below which the crack ceased to grow. A steady crack growth occurred when the applied electric field exceeded this threshold. An empirical model for crack growth was obtained. Domain-switching effect and fracture-mechanics concepts were used to explain the observed crack closure and crack growth under electric loads.