Combined three-dimensional (3D) mapping of (micro-)structures with elemental and crystalline phase variations is of significant importance for the characterization of materials. Neutron wavelength selective imaging is a spectral imaging technique that exploits unique contrast differences e.g. for mapping dissimilar elemental, isotope, or phase compositions, and has the particular advantage of being applicable to sample volumes on the meso- and macroscale. While being mostly applied as radiography (2D) so far, we herein report that the extension to tomography allows for the display of the full spectral information for every voxel and in 3D. The development is supported by example data from a continuous as well as a pulsed neutron source. As a practical example, we collected 4D data sets (3D + spectral) of plastically deformed metastable stainless steel and herein demonstrate an improved quantification strategy for crystalline phase fractions. These exemplary results illustrate that localized phase transformations can be quantified even in complex geometries within centimeter-sized samples, and we will discuss the limits and future prospects of the technique that is not limited to crystalline materials.

具有元素和晶体相变的（微）结构的组合三维（3D）映射对于材料的表征非常重要。中子波长选择性成像是一种光谱成像技术，它利用独特的对比度差异（例如，用于绘制不同的元素，同位素或相组成），并具有适用于中尺度和宏观尺度的样本量的特殊优势。到目前为止，虽然目前大部分被用作放射线照相（2D），但我们在此报告，层析成像技术的扩展允许以3D形式显示每个体素的完整光谱信息。来自连续和脉冲中子源的示例数据支持了这一发展。举一个实际的例子 我们收集了塑性变形亚稳态不锈钢的4D数据集（3D +光谱），并在此证明了改进的结晶相分数定量策略。这些示例性结果说明，即使在厘米大小的样本中，即使在复杂的几何形状中，也可以量化局部相变，并且我们将讨论不限于晶体材料的技术的局限性和未来前景。