Abstract

In situ three-dimensional X-ray synchrotron tomography was used to visualize and quantify the fatigue crack initiation and growth from corrosion pits in high strength aluminum alloys. Corrosion pitted Al 7075 and Al 7475 samples of peak-aged, over-aged, and highly over-aged conditions were prepared by soaking in 3.5 wt pct NaCl solution for fifteen days. These samples were fatigue tested in situ in 3.5 wt pct NaCl solution using synchrotron X-ray tomography to analyze the fatigue crack initiation and growth characteristics (4D). Increases in maximum pit depth and fatigue crack growth rate variability were found with increased aging. A detailed analysis of crack morphology and deflection, as a function of aging, was carried out and it discussed.

中文翻译：

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使用原位同步加速器X射线断层扫描技术对Al 7XXX合金中的疲劳裂纹萌生和腐蚀坑的3D时间分辨观察

抽象的

原位三维X射线同步加速器层析成像用于可视化和量化高强度铝合金中疲劳裂纹的产生和腐蚀点的增长。通过在3.5 wt％的NaCl溶液中浸泡15天，制备了峰值，过时和高度过时的腐蚀点蚀Al 7075和Al 7475样品。使用同步加速器X射线断层扫描术在3.5 wt％的NaCl溶液中对这些样品进行原位疲劳测试，以分析疲劳裂纹萌生和生长特性（4D）。随着时效的增加，发现最大凹坑深度和疲劳裂纹扩展速率变异性增加。对裂纹形态和挠度随时效的变化进行了详细分析，并进行了讨论。