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.

可以通过亚微米计超高分辨率同步辐射X射线计算机（CT，ct，ct，ct，ct，ct，ct，ct，ct，ct，ct，ct，ct，ct，ct rocts ocker（CT，ct，ct，ct，ct，ct，ct），可以通过3D，原位和高密度（间隔小于1微米）以3D，原位和高密度（间隔小于1微米）进行测量的实际局部裂纹驱动力（模式I，II和III的裂纹）。通过微观结构跟踪的数百个功能已经实现了这一点，并且可以将其进一步扩展到数千个功能级别。仅通过特殊的材料测试程序（例如光弹，Moire干涉法和苛性）才能在标本表面上使用的测量值很容易应用于材料内部。通常，局部裂纹的驱动力不仅受到宏观施加的应力，而且还受到各种裂纹屏蔽/抗屏蔽效应的影响，例如由于实际材料的微观结构而引起的裂纹偏转，损伤进化和裂纹闭合现象。开发的过程已应用于在铝合金中传播的疲劳裂纹。实验是在ESRF的Spring-8和ID19的Imaging Beam Line BL20B2和BL47XU上进行的，并验证了其可行性。通过分析每个裂纹尖端上实际局部裂纹驱动力的机制，可以通过定量澄清各种裂纹屏蔽/防挡效应（例如裂纹挠度，损伤进化和裂纹封闭现象）的贡献。通过将GA掺入Nano-Scopic结构（例如晶粒边界）中，它们可以可视化。晶界的可视化已成功地铸造了材料，锻造材料和多孔铝材，这表明了所开发的技术的有效性。