Localized deformation during fracture of high-strength aluminum alloy
Localized deformation during fracture of high-strength aluminum alloy
复制标题
高强铝合金断裂过程中的局部变形
DOI：
10.1016/j.proeng.2011.04.427
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
M.Kobayashi
中科院分区：
文献类型：
--
作者：
H.Toda;A.Miyawaki;K.Uesugi;Y.Suzuki;M.Kobayashi
利用X射线显微层析成像技术对高强铝合金的裂纹萌生和扩展进行了观察。应用作者开发的计算局部裂纹驱动力的程序，如J和CTOD，分析了局部裂纹的萌生和扩展行为。前者是通过跟踪位于高密度层析成像中的微结构特征来实现的。后者直接在3D图像中测量。为了提高显微组织跟踪技术的精度，引入了轨迹预测技术，从而实现了跟踪标记率的大幅提高。观察到裂纹尖端前方大量微裂纹的形成，随后是裂纹的过早萌生和扩展。结果表明，微裂纹的产生远远超出了传统断裂力学所预测的大应变区(10倍以上)。目前的方法可以提供一种非常有效的方法来定量评估这种三维局部断裂行为。
X-ray microtomography has been utilized for the observation of crack initiation and growth in a high-strength aluminum alloy. Procedures for evaluating local crack-driving forces such as J and CTOD, which were developed by the present authors, have been applied to analyze localized crack initiation and growth behaviors. The former is realized by tracking microstructural features that are located in tomographic imaged in high density. The latter is directly measured in 3D images. In order to raise the accuracy of the microstructural tracking technique, a trajectory prediction technique has been introduced, thereby substantial improvement in the ratio of tracked markers has been realized. Extensive formation of micro cracks ahead of a crack tip has been observed, being followed by premature crack initiation and growth. It has been clarified that the micro cracking occurs far beyond (more than 10 times) a large strain region that has been predicted in the conventional fracture mechanics. The current methods could offer a highly effective way of assessing such 3D local fracture behavior quantitatively.