Far-field high-energy diffraction microscopy: a tool for intergranular orientation and strain analysis
Far-field high-energy diffraction microscopy: a tool for intergranular orientation and strain analysis
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DOI：
10.1177/0309324711405761
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发表时间：
2011-01-01
影响因子：
1.6
通讯作者：
Miller, M. P.
中科院分区：
文献类型：
--
作者：
Bernier, J. V.;Barton, N. R.;Miller, M. P.
在高能同步X射线衍射的背景下，提出了远场高能衍射显微技术。对于照明的多晶体中的每个颗粒，体积平均晶格取向、晶格应变张量和质心(COM)坐标可以被确定为高精度：分别优于0.05度、1×10(-4)和0.1像素。由于可以得到完整的晶格应变张量，相应的平均应力张量可以用单晶弹性模来明确地计算出来。介绍了一种新的取向指标化和晶胞精细化公式，并用两个例子进行了演示：第一，具有已知COM坐标的单晶红宝石标准的连续指标化和晶格精细化；第二，使用几个样品旋转范围并考虑了实验不确定性的影响，对819个单个颗粒的模拟衍射数据进行了指标化和精细化。高能(即50keV)X射线的获取速度和穿透深度使这项技术成为研究现场应变/应力演变以及残余应力分析的理想技术。
The far-field high-energy diffraction microscopy technique is presented in the context of high-energy synchrotron x-ray diffraction. For each grain in an illuminated polycrystalline volume, the volume-averaged lattice orientations, lattice strain tensors, and centre-of-mass (COM) coordinates may be determined to a high degree of precision: better than 0.05 degrees, 1 x 10(-4), and 0.1 pixel, respectively. Because the full lattice strain tensors are available, corresponding mean stress tensors may be calculated unambiguously using single-crystal elastic moduli. A novel formulation for orientation indexing and cell refinement is introduced and demonstrated using two examples: first, sequential indexing and lattice refinement of a single-crystal ruby standard with known COM coordinates; and second, indexing and refinement of simulated diffraction data from an aggregate of 819 individual grains using several sample rotation ranges and including the influence of experimental uncertainties. The speed of acquisition and penetration depth achievable with high-energy (that is, >50 keV) x-rays make this technique ideal for studies of strain/stress evolution in situ, as well as for residual stress analysis.