发表机构
Technical University of Denmark; Paul Scherrer Institut; Lund University; Aarhus University（丹麦技术大学; 保罗谢尔研究所; 隆德大学; 奥胡斯大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对多晶衍射介于粉末与逐晶索引之间的困境，提出基于自适应基的织构层析成像，以峰索引候选取向替代均匀网格，提升角分辨率，在模拟和实验中实现更优的晶粒与亚晶粒边界描绘。
AI 中文摘要
在利用窄束进行的空间分辨X射线衍射实验中，多晶材料的衍射图样往往介于两种成熟方法适用场景之间。细晶粒、弱织构的微观结构产生平滑的德拜-谢勒环，适用于粉末和张量层析成像方法；而粗大、弱变形的晶粒则产生可逐晶索引的孤立斑点。许多重要的多晶材料，包括塑性变形金属、含有复杂孪晶微观结构的马氏体和铁弹材料，以及具有强织构或晶粒尺寸不均匀的地质集合体，会产生介于上述两种极限之间的斑点状衍射环，其峰形展宽且相互重叠。织构层析成像通过从衍射数据重建空间取向分布来解决这一难题。然而，传统织构层析成像缺乏尖锐分布所需的角分辨率，而逐晶索引可能引入边界伪影并低估晶粒内部取向差。本工作引入基于自适应基的织构层析成像。从峰索引获得的候选取向替代均匀取向网格，从而实现更高的角分辨率。与传统织构层析成像类似，该方法在每个体素中重建完整的取向分布函数，使体素能够保留来自多个晶粒、亚晶粒或畴的贡献，而非被迫采用单一取向。模拟铝多晶实验表明，与均匀基织构层析成像和逐点扫描三维X射线衍射（3DXRD）相比，该方法能更清晰地描绘晶粒和亚晶粒边界，同时降低晶粒内部取向误差。对拉伸变形铝的实验演示表明，可绘制取向展宽达数度的块体晶粒和亚晶粒结构。
英文摘要
In spatially resolved X-ray diffraction experiments using narrow beams, diffraction patterns from polycrystalline materials often fall between two well-served regimes. Fine-grained, weakly textured microstructures produce smooth Debye-Scherrer rings suited to powder- and tensor-tomography methods, whereas coarse, weakly deformed grains produce isolated spots that can be indexed grain by grain. Many important polycrystalline materials, including plastically deformed metals, martensitic and ferroelastic materials containing complex twin microstructures, and geological aggregates with strong texture or heterogeneous grain size, produce spotty diffraction rings with broadened and overlapping peaks between these limits. Texture tomography addresses this regime by reconstructing spatial orientation distributions from diffraction data. Here, conventional texture tomography lacks the angular resolution needed for sharp distributions, while grain-by-grain indexing can introduce boundary artifacts and underestimate intragranular misorientation. This work introduces basis-adaptive texture tomography. Candidate orientations obtained from peak indexing replace the uniform orientation grid, achieving higher angular resolution. Like conventional texture tomography, it benefits from reconstructing a full orientation distribution function in each voxel, allowing voxels to retain contributions from multiple grains, subgrains or domains rather than being forced into a single orientation. Simulated aluminum polycrystals show improved delineation of grain and sub-grain boundaries accompanied by lower intragranular orientation errors compared with uniform-basis texture tomography and point-by-point scanning 3DXRD. An experimental demonstration on tensile-deformed aluminum shows that bulk grain and subgrain structures with orientation spreads of several degrees can be mapped.
Comments28 pages, 13 figures
