Measurement of the components of plastic displacement gradients in three dimensions
Measurement of the components of plastic displacement gradients in three dimensions
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三维塑性位移梯度分量的测量
DOI：
10.1117/12.559641
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发表时间：
2004
影响因子：
2.5
通讯作者：
J. Wert
中科院分区：
文献类型：
--
作者：
S. F. Nielsen;F. Beckmann;R. Godiksen;Kristoffer Haldrup;H. Poulsen;J. Wert
提出了一种非破坏性表征块状材料塑性变形的方法。该方法是基于X射线吸收显微层析成像调查使用X射线从同步辐射源。该方法可以应用于含有标记物颗粒的材料，所述标记物颗粒具有与基质材料的原子序数显著不同的原子序数。在HASYLAB/DESY的专用显微断层扫描仪上，在光束线BW 2处采集了含有平均粒径为7 μm的W颗粒的圆柱形铝样品的数据。在HASYLAB目前的空间分辨率下，标记颗粒的最小可检测尺寸为1-2 μm。根据应变确定在1 mm 3内的所有检测到的标记物颗粒的位置（x，y，z）。样品沿圆柱体的轴沿着逐步压缩变形。在每个变形步骤后进行断层扫描。在一系列图像分析步骤以识别单个颗粒的质心和连续断层重建的对准之后，可以跟踪单个颗粒的位移作为外部应变的函数。然后使用粒子位移来识别局部位移梯度分量，由此可以确定局部3D塑性应变张量。这使我们能够映射应变分量作为变形金属固体内部位置的函数。
A method for non-destructive characterization of plastic deformation in bulk materials is presented. The method is based on X-ray absorption microtomography investigations using X-rays from a synchrotron source. The method can be applied to materials that contain marker particles, which have an atomic number significantly different from that of the matrix material. Data were acquired at the dedicated microtomography instrument at beamline BW2 at HASYLAB/DESY, for a cylindrical aluminium sample containing W particles with an average particle diameter of 7 μm. The minimum detectable size of the maker particles is 1-2 μm with the present spatial resolution at HASYLAB. The position (x,y,z) of all the detected marker particles within 1 mm3 was determined as function of strain. The sample was deformed in stepwise compression along the axis of the cylinder. A tomographic scan was performed after each deformation step. After a series of image analysis steps to identify the centre of mass of individual particles and alignment of the successive tomographic reconstructions, the displacements of individual particles could be tracked as a function of external strain. The particle displacements are then used to identify local displacement gradient components, from which the local 3D plastic strain tensor can be determined. This allows us to map the strain components as a function of location inside a deforming metallic solid.