Realisation of 3D In-situ Assessment of Local Crack Driving Forces via Ultra-high Resolution Synchrotron X-ray CT

通过超高分辨率同步加速器X射线CT实现局部裂纹驱动力的3D原位评估

基本信息

批准号：
15560606
负责人：
TODA Hiroyuki
金额：
$ 1.41万
依托单位：
Toyohashi University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

The procedure, by which real local crack driving forces (Modes I,II and III crack driving forced along crack front) can be measured in 3D, in-situ and in high density (at intervals less than 1 micron) via the sub-micrometer ultra-high resolution synchrotron radiation X-ray computed tomography (CT, hereinafter), has been developed in this study. This has been realized by microstructural tracking of several hundred features, and this can be further extended to several ten thousand features level. Measurements, which had been available only on specimen surface by the special material test procedures such as photoelasticity, Moire interferometry and caustics, have been readily applied to material interior. In general, the local crack driving forces are intricately and remarkably affected not only by macroscopic applied stress, but also by various crack shielding/anti-shielding effects, such as crack deflection, damage evolution and crack closure phenomenon, due to microstructures of the actual materials. The procedure developed has been applied to fatigue cracks propagating in aluminum alloys. The experiments were performed at the imaging beam lines BL20B2 and BL47XU of the SPring-8 and ID19 of the ESRF, and its feasibility was verified. By analyzing mechanisms of real local crack driving forces at each crack-tip point, the contributions by various crack shielding/anti-shielding effects, such as crack deflection, damage evolution and crack closure phenomenon, could be quantitatively clarified.By doping Ga into nano-scopic structures such as grain boundaries, they could be visualized. The visualization of the grain boundary has been succeeded in casting materials, wrought materials and porous aluminum materials, which indicates the effectiveness of the technique developed.

该程序可以通过亚微米以 3D、原位和高密度（间隔小于 1 微米）测量真实的局部裂纹驱动力（沿着裂纹前沿的模式 I、II 和 III 裂纹驱动力）本研究开发了超高分辨率同步辐射X射线计算机断层扫描（CT，以下简称CT）。这已经通过数百个特征的微观结构跟踪来实现，并且可以进一步扩展到数万个特征水平。以前只能通过光弹性、莫尔干涉测量和焦散等特殊材料测试程序在样品表面进行的测量，现在可以很容易地应用于材料内部。一般来说，局部裂纹驱动力不仅受到宏观施加应力的复杂而显着的影响，而且由于实际材料的微观结构，还受到各种裂纹屏蔽/反屏蔽效应的影响，例如裂纹偏转、损伤演化和裂纹闭合现象。材料。所开发的程序已应用于铝合金中扩展的疲劳裂纹。在ESRF的SPring-8和ID19的成像光束线BL20B2和BL47XU上进行了实验，验证了其可行性。通过分析每个裂纹尖端点的真实局部裂纹驱动力的机制，可以定量地阐明各种裂纹屏蔽/反屏蔽效应的贡献，例如裂纹偏转、损伤演化和裂纹闭合现象。 - 诸如晶界之类的可见结构，它们可以被可视化。晶界的可视化已在铸造材料、变形材料和多孔铝材料中取得成功，这表明了所开发技术的有效性。