Grain misorientations in partially molten olivine aggregates: an electron backscatter diffraction study
Grain misorientations in partially molten olivine aggregates: an electron backscatter diffraction study
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部分熔融橄榄石聚集体中的晶粒取向错误：电子背散射衍射研究
DOI：
10.1007/s002690050176
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发表时间：
1999
影响因子：
1.4
通讯作者：
J. F. Fitz Gerald
中科院分区：
文献类型：
--
作者：
U. Faul;J. F. Fitz Gerald
摘要：在平均晶粒尺寸超过 35 μm 且玄武岩熔体分数较低的橄榄石多晶聚集体中，在 15 至 25 天的高压和高温平衡时间后，观察到润湿和无熔体晶界。为了评估润湿行为对相邻晶粒相对取向的可能依赖性，使用基于 SEM 的技术电子背散射衍射 (EBSD) 来确定晶粒取向。根据晶粒取向，计算相邻晶粒的相对取向，其表示为取向差轴/角度对。无熔体晶界的取向差角和轴的分布与纯随机分布显着不同，而润湿晶界的取向角和轴的分布在统计上与随机分布无法区分。因此，两个相邻晶粒的相对取向会影响它们共同晶界的特征。然而，没有观察到朝向特殊（重合位点晶格）取向差轴的聚集，推断特殊取向差和一般取向差之间的能量差异太小，不足以导致晶粒生长过程中优选取向差的发展。
Abstract In polycrystalline aggregates of olivine with mean grain sizes above 35 μm plus a low basaltic melt fraction, both wetted and melt-free grain boundaries are observed after equilibration times at high pressures and temperatures of between 15 and 25 days. In order to assess a possible dependence of the wetting behaviour on the relative orientation of neighbouring grains, a SEM based technique, electron backscatter diffraction (EBSD), is used to determine grain orientations. From the grain orientations relative orientations of neighbouring grains are calculated, which are expressed as misorientation axis/angle pairs. The distribution of misorientation angles and axes of melt-free grain boundaries differ significantly from a purely random distribution, whereas those of wetted grain boundaries are statistically indistinguishable from the random distribution. The relative orientation of two neighbouring grains therefore influences the character of their common grain boundary. However, no clustering towards special (coincident site lattice) misorientation axes is observed, with the inference that the energy differences between special and general misorientations are too small to lead to the development of preferred misorientations during grain growth.