Quantifying the grain boundary resistance against slip transfer by experimental combination of geometric and stress approach using stage-I-fatigue cracks
Quantifying the grain boundary resistance against slip transfer by experimental combination of geometric and stress approach using stage-I-fatigue cracks
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DOI：
10.1080/14786435.2016.1235289
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发表时间：
2016-09
影响因子：
1.6
通讯作者：
F. Schäfer;Laura Weiter;M. Marx;C. Motz
中科院分区：
文献类型：
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作者：
F. Schäfer;Laura Weiter;M. Marx;C. Motz
近年来，许多研究小组通过双晶和微试样实验研究了位错与晶界的相互作用。部分地，这些实验与离散位错动力学的补充模拟相结合，但晶界对滑移转移阻力的定量数据仍然缺失。在这个可行性研究的第一个结果，我们使用阶段-I-疲劳裂纹作为高度本地化的位错源与著名的伯格斯矢量研究在裂纹尖端和选定的晶界前的塑性区中的位错之间的相互作用。在晶界处的应力集中计算与断裂的无位错区模型使用位错密度分布在塑性区从滑移轨迹高度轮廓测量原子力显微镜。从常见的几何模型计算的晶界电阻值进行比较，在晶界的局部应力分布。因此，可以量化晶界阻力，并将联合收割机几何和应力方法用于晶界阻力以防止滑移转移到一个独立的概念。因此，基于临界应力概念的晶界电阻效应的预测仅在了解晶界的几何参数即参与晶粒的取向和晶界平面的取向的情况下是可能的。
Abstract In recent studies, many groups have investigated the interaction of dislocations and grain boundaries by bi-crystals and micro-specimen experiments. Partially, these experiments were combined with supplementary simulations by discrete dislocation dynamics, but quantitative data for the grain boundary resistance against slip transfer is still missing. In this feasibility study with first results, we use stage-I-fatigue cracks as highly localised sources for dislocations with well-known Burgers vectors to study the interaction between dislocations in the plastic zone in front of the crack tip and selected grain boundaries. The stress concentration at the grain boundary is calculated with the dislocation-free zone model of fracture using the dislocation density distribution in the plastic zone from slip trace height profile measurements by atomic force microscopy. The grain boundary resistance values calculated from common geometric models are compared to the local stress distribution at the grain boundaries. Hence, it is possible to quantify the grain boundary resistance and to combine geometric and stress approach for grain boundary resistance against slip transfer to a self-contained concept. As a result, the prediction of the grain boundary resistance effect based on a critical stress concept is possible with knowledge of the geometric parameters of the grain boundary only, namely the orientations of both participating grains and the orientation of the grain boundary plane.