High‐Precision Measurement of Temperature Factors for NiAl by Convergent‐Beam Electron Diffraction
High‐Precision Measurement of Temperature Factors for NiAl by Convergent‐Beam Electron Diffraction
复制标题
利用会聚束电子衍射高精度测量 NiAl 的温度因素
DOI：
10.1107/s0108767397010969
复制
发表时间：
1998
期刊：
影响因子：
--
通讯作者：
J. Mayer
中科院分区：
文献类型：
--
作者：
W. Nüchter;A. Weickenmeier;J. Mayer
采用会聚束电子衍射技术对NiAl金属间化合物的温度因子进行了高精度测量。使用慢扫描CCD相机在零能量损失下将图案记录在能量过滤透射电子显微镜中。标本倾斜系统行方向。在这种新的方法中，数据提取的明场光盘以及从几个高阶暗场光盘沿沿着线扫描。通过将布洛赫波模拟拟合到强度分布来确定温度因子。温度因子采用谐波近似。对于B_2相NiAl，在100K时得到平均热位移u（Ni）= 5.5 ± 0.1pm和u（Al）= 5.7 ± 0.1pm。一个非常详细的误差分析，并讨论和量化的随机和系统误差。
Convergent-beam electron diffraction is applied to measure the temperature factors of the intermetallic phase NiAl with high accuracy. The patterns are recorded in an energy-filtering transmission electron microscope at zero energy loss using a slow-scan CCD camera. The specimens were tilted in systematic row orientation. In this new approach, data are extracted from the bright-field disc as well as from several high-order dark-field discs along line scans. The temperature factors are determined by fitting Bloch-wave simulations to the intensity profiles. The harmonic approximation for temperature factors is used. For B2-phase NiAl, mean thermal displacements u(Ni) = 5.5 ± 0.1 and u(Al) = 5.7 ± 0.1 pm are obtained at 100 K. A very detailed error analysis is given, and stochastic and systematic errors are discussed and quantified.