Intragranular boundaries are important features of polycrystalline materials and impact on many physical and chemical properties. Knowledge of their physical orientation is often crucial to explain such properties. However, it has proved difficult to determine the complete orientation of intragranular boundaries, which involves the misorientation angle and axis about which the adjacent crystal lattices need to be rotated to bring them into coincidence and also the physical orientation of the boundary plane, expressed by the plunge and azimuth of its normal; five parameters in total. Here we present a simple and practical manual method to determine the complete intragranular boundary orientation in any crystal system. The method is developed on geometrical relationships exhibited between electron channelling patterns across a common boundary but then extended for use with electron backscattered diffraction patterns. The method recognises the channelling/diffraction band, equivalent to a crystal lattice plane, not displaced across a boundary; the boundary rotation axis must be the normal to this plane. Geometrical relationships between the boundary trace, the non-displaced band/plane and their respective plane normals constrain boundary orientation to two alternative symmetrically equivalent solutions and are evaluated via stereographic projection. The choice of solution is guided by comparison with the presence or absence of a similarly oriented band/plane observed in the original channelling/diffraction patterns. The method therefore conforms to the low-index crystallographic lattice plane and dislocation model for intragranular boundary formation and defines boundary orientation in terms of total angular misorientation due to tilt and twist components and the orientation of the boundary plane. Examples of intragranular boundary orientation determination using this method are provided in olivine. Results are compared to and differ from those obtained via conventional misorientation analysis, which only rotates adjacent crystal lattices into parallelism and does not consider boundary plane orientation. Potential extrapolation of the new method to intergranular boundaries is also considered

晶内边界是多晶材料的重要特征，并影响许多物理和化学性质。了解它们的物理方向对于解释这些特性通常是至关重要的。然而，已证明很难确定晶内边界的完整取向，这涉及到相邻晶格需要旋转以使其重合的取向错误角度和轴，以及边界平面的物理取向，表示为其正常的俯冲和方位角；共五个参数。在这里，我们提出了一种简单实用的手动方法来确定任何晶体系统中完整的晶内边界取向。该方法是在跨越公共边界的电子通道图案之间表现出的几何关系上开发的，但随后扩展到用于电子背散射衍射图案。该方法识别通道/衍射带，相当于晶格平面，不会跨越边界；边界旋转轴必须是该平面的法线。边界轨迹、非位移带/平面和它们各自的平面法线之间的几何关系将边界方向限制为两个替代的对称等效解，并通过立体投影进行评估。通过与在原始通道/衍射模式中观察到的类似定向带/平面的存在或不存在进行比较来指导解决方案的选择。因此，该方法符合用于晶内边界形成的低指数晶体晶格平面和位错模型，并根据由于倾斜和扭曲分量以及边界平面的取向而导致的总角度错误取向来定义边界取向。在橄榄石中提供了使用此方法确定晶内边界取向的示例。结果与通过常规错误取向分析获得的结果进行比较并有所不同，后者仅将相邻晶格旋转为平行，而不考虑边界面取向。还考虑了新方法对晶间边界的潜在外推 在橄榄石中提供了使用此方法确定晶内边界取向的示例。结果与通过常规错误取向分析获得的结果进行比较并有所不同，后者仅将相邻晶格旋转为平行，而不考虑边界面取向。还考虑了新方法对晶间边界的潜在外推 在橄榄石中提供了使用此方法确定晶内边界取向的示例。结果与通过常规错误取向分析获得的结果进行比较并有所不同，后者仅将相邻晶格旋转为平行，而不考虑边界面取向。还考虑了新方法对晶间边界的潜在外推