Factors affecting the accuracy of high resolution electron backscatter diffraction when using simulated patterns
Factors affecting the accuracy of high resolution electron backscatter diffraction when using simulated patterns
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DOI：
10.1016/j.ultramic.2010.08.001
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发表时间：
2010-11-01
期刊：
影响因子：
2.2
通讯作者：
Wilkinson, A. J.
中科院分区：
文献类型：
--
作者：
Britton, T. B.;Maurice, C.;Wilkinson, A. J.
高分辨率EBSD直接比较在扫描电子显微镜中产生的电子背散射图案（EBSP），以测量相对应变和旋转，精度接近10（-4）应变和10（-4）rad（0.006度）旋转。然而，绝对应变和旋转的测量需要已知应变和取向的参考EBSP（或已知应变的远场区域）。最近的建议，使用模拟EBSPs与已知的应变表现出很大的希望。然而，需要精确测量实验几何形状（图案中心）。图中心的一般不确定度为0.5%，导致应变状态的不确定度接近10（-3）。用于EBSP捕获的紧凑型透镜中的像差也可导致对应于实验EBSP与模拟EBSP之间的+/-10（-3）的应变/旋转的图像移位。模拟EBSP可以使用动力学或运动学模型（或两者的组合）生成。模拟模型的选择对测量的位移有显著影响，特别是在区域轴和高结构因子带，由于大的强度变化，并且对于简单的运动学模拟，可能导致测量异常位移，从而导致错误的应变测量。已知应变的校准样品提供了一种测量实验几何形状的方法，但不精确的载物台移动与SEM中的高景深相结合也可能导致类似于10（-3）的应变不确定性。(C)2010爱思唯尔有限公司版权所有。
High resolution EBSD directly compares electron backscattering patterns (EBSPs), generated in a scanning electron microscope, to measure relative strain and rotation to a precision of similar to 10(-4) in strain and 10(-4) rad (0.006 degrees) in rotation. However the measurement of absolute strain and rotation requires reference EBSPs of known strain and orientation (or a far field region of known strain). Recent suggestions of using simulated EBSPs with known strain show much promise. However precise measurement of the experimental geometry (pattern centre) is required. Common uncertainties of 0.5% in pattern centre result in uncertainty of similar to 10(-3) in strain state. Aberrations in the compact lenses used for EBSP capture can also result in image shifts that correspond to strains/rotations of +/- 10(-3) between experimental and simulated EBSPs. Simulated EBSPs can be generated using dynamical or kinematic models (or a combination of the two). The choice in simulation model has a significant effect on the measured shifts, particularly at zone axis and high structure factor bands, due to large intensity variations, and for simple kinematic simulations can result in the measurement of rogue shifts and thus erroneous strain measurements. Calibrant samples of known strain provide a method of measuring the experimental geometry but imprecise stage movement combined with the high depth of field in the SEM could also result in uncertainties in strain of similar to 10(-3). (C) 2010 Elsevier B.V. All rights reserved.