Fracture of metal/ceramic laminates - I. Transition from single to multiple cracking
Fracture of metal/ceramic laminates - I. Transition from single to multiple cracking
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DOI：
10.1016/s1359-6454(98)00357-7
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发表时间：
1999-01-15
期刊：
影响因子：
9.4
通讯作者：
Derby, B
中科院分区：
文献类型：
--
作者：
Hwu, KL;Derby, B
在Al/Al_2O_3、Cu/Al_2O_3和Ni/Al_2O_3三种金属/陶瓷层合板系统中，研究了在一定的金属/陶瓷厚度比（t（m）/t（c））范围内，裂纹尖端由单裂纹扩展向多层裂纹扩展的转变。多裂纹发生在临界值t（m）/t（c）以上，临界值随着等效约束金属屈服应力与平均陶瓷断裂应力的比值σ（e）/σ（c）的减小而增大。这些结果被证明是不一致的预测的线弹性断裂力学（LEFM）模型，它认为作为一个桥接的整体裂纹的开裂层压板，为较低的金属屈服强度铜/氧化铝和铝/氧化铝层压板。修正模型考虑了裂纹尾流中陶瓷层中的应力分布由低于σ（e）/σ（c）比值临界值的剪滞决定的极限情况。这种组合模型被证明可以更准确地预测从单一到多个裂纹在三个层压板类型的过渡，并预测在多个裂纹试样的陶瓷层裂纹间距。(C)1999《冶金学报》出版社：Elsevier Science Ltd保留所有灯光。
The transition from single crack extension to multiple laminate cracking near the crack tip has been studied over a range of metal/ceramic thickness ratios (t(m)/t(c)), in three metal/ceramic laminate systems: Al/alumina, Cu/alumina and Ni/alumina. Multiple cracking occurs above a critical value of t(m)/t(c), with the critical value increasing with decreasing ratio of equivalent constrained metal yield stress to mean ceramic fracture stress, sigma(e)/sigma(c). These results are shown to be inconsistent with the predictions of a linear elastic fracture mechanics (LEFM) model, which considers a cracked laminate as a bridged monolithic crack, for the lower metal yield strength Cu/alumina and Al/alumina laminates. A modified model considers a limiting case where the stress distribution in the ceramic layers in the crack wake is determined by shear-lag below a critical value of the ratio sigma(e)/sigma(c). This combined model is shown to predict more accurately the transition from single to multiple cracking in the three laminate types and also to predict the ceramic layer crack spacing in the multiple cracked specimens. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd All lights reserved.