The dislocations contrast factors of cubic crystals in the Zener constant range between zero and unity
The dislocations contrast factors of cubic crystals in the Zener constant range between zero and unity
复制标题
立方晶体齐纳常数在零和一范围内的位错对比因子
DOI：
10.1154/1.1471520
复制
发表时间：
2002
影响因子：
0.5
通讯作者：
T. Ungár
中科院分区：
文献类型：
--
作者：
I. Dragomir;T. Ungár
由于晶体的细小和晶格缺陷的存在，使衍射峰的峰形变宽。多晶材料粉末的应变展宽通常是关于hkl指数的各向异性。这种应变各向异性已被很好地解释，假设位错是晶格扭曲的主要来源之一。对于这种互操作来说，位错对比因子的知识是不可避免的。在前人的工作中，立方晶体的弹性常数在0.5≤Az≤8范围内的理论对比因子被评估。大量离子晶体和许多难熔金属的弹性各向异性Az远低于0.5。在本工作中，我们研究了这一低各向异性常数范围的对比度因子。对球磨PbS、Nb和纳米CeO2进行了计算和相应的峰形分析。
Diffraction peak profiles broaden due to the smallness of crystallites and the presence of lattice defects. Strain broadening of powders of polycrystalline materials is often anisotropic in terms of the hkl indices. This kind of strain anisotropy has been shown to be well interpreted assuming dislocations as one of the major sources of lattice distortions. The knowledge of the dislocation contrast factors are inevitable for this interoperation. In a previous work the theoretical contrast factors were evaluated for cubic crystals for elastic constants in the Zener constant range 0.5≤Az≤8. A large number of ionic crystals and many refractory metals have elastic anisotropy, Az, well below 0.5. In the present work the contrast factors for this lower anisotropy-constant range are investigated. The calculations and the corresponding peak profile analysis are tested on ball milled PbS and Nb and nanocrystalline CeO2.