Interaction of microcracks with selected interfaces : Focused ion beam for a systematic crack initiation
Interaction of microcracks with selected interfaces : Focused ion beam for a systematic crack initiation
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微裂纹与选定界面的相互作用：用于系统裂纹萌生的聚焦离子束
DOI：
10.1016/j.msea.2006.07.042
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发表时间：
2006
期刊：
影响因子：
6.4
通讯作者：
C. Holzapfel
中科院分区：
文献类型：
--
作者：
M. Marx;W. Schäf;H. Vehoff;C. Holzapfel
新引入的聚焦离子束技术与高分辨率扫描电子显微镜相结合，是第一种在选定的相和晶界前用理想化的裂纹参数引发人工微裂纹的方法。在通过电子背散射衍射进行完整的样品表征并计算每个晶粒内的优选滑移系之后，选择感兴趣的边界。这种组合的表征和操纵技术在微观尺度上使第一次系统的调查与微观结构障碍的相互作用的短裂纹定量检查田中，纳瓦罗和德洛斯里奥斯的模型。本文提出了不同的缺口几何形状，从单线到硬币形表面裂纹的人工微裂纹的起始。它表明，不仅可以选择裂纹的起始点。此外，裂纹扩展路径可以通过直接在具有高施密德因子的滑移系上引发裂纹来预先确定。作为第一个结果的晶界上的裂纹扩展速率的定向凝固镍基高温合金的不同取向差角的影响。最后讨论了该方法作为一种强有力的晶界工程技术。
The newly introduced combination of focused ion beam technique with high resolution scanning electron microscopy is the first method to initiate artificial microcracks with idealized crack parameters in front of selected phase- and grain boundaries. The boundaries of interest are selected after a complete sample characterization by Electron Back Scatter Diffraction and a calculation of the preferred slip systems within each grain. This combination of characterizing- and manipulating techniques on a microscale enables for the first time a systematic investigation of the interaction of short cracks with microstructural barriers to check the models of Tanaka, Navarro and De Los Rios quantitatively. In this paper, different notch geometries from single lines to penny shaped surface cracks for the initiation of artificial microcracks are presented. It is shown that not only the starting point of a crack can be selected. Further, the crack propagation path can be predetermined by initiating the crack directly on a slip system with a high Schmid factor. As a first result the influence of grain boundaries with different misorientation angles on the crack propagation rate for a directionally solidified nickel-based superalloy is shown. Finally this method is discussed as a powerful technique for grain boundary engineering.