Synchrotron x-rays are a powerful tool to probe real-time changes in the microstructure of materials as they respond to an external stimulus, such as phase transformations that take place in response to a change in temperature. X-ray imaging techniques include radiography and tomography, and have been steadily improved over the last decades so that they can now resolve micrometer-scale or even finer structural changes in bulk specimens over time scales of a second or less. Under certain conditions, these imaging approaches can also give spatially resolved chemical information. In this article, we focus on the liquid to solid transformation of metallic alloys and the temporal and spatial resolution of the accompanying segregation of alloying elements. The solidification of alloys provides an excellent case study for x-ray imaging because it is usually accompanied by the progressive, preferential segregation of one or more of the alloying elements to either the solid or the liquid, and gives rise to surprisingly complex chemical segregation patterns. We describe chemical mapping investigations of binary and quasi-binary alloys using radiography and tomography, and recent developments in x-ray fluorescence imaging that offer the prospect of a more general, multielement mapping technique. Future developments for synchrotron-based chemical mapping are also considered.

同步加速器X射线是探测材料微观结构实时变化的强大工具，因为它们会响应外部刺激，例如响应温度变化而发生的相变。X射线成像技术包括射线照相和断层摄影，并且在过去的几十年中得到了稳步的改进，因此它们现在可以解决微米级甚至更大的结构变化（在一秒或更短的时间范围内）。在某些条件下，这些成像方法还可提供空间分辨的化学信息。在本文中，我们着重于金属合金的液体至固体转变以及伴随的合金元素偏析的时间和空间分辨率。合金的固化为X射线成像提供了一个很好的案例研究，因为它通常伴随着一种或多种合金元素逐渐，优先地偏析到固体或液体中，并产生令人惊讶的复杂化学偏析图。我们描述了使用射线照相和层析成像技术对二元和准二元合金进行化学作图研究，以及x射线荧光成像的最新发展，为更通用的多元素作图技术提供了前景。还考虑了基于同步加速器的化学绘图的未来发展。我们描述了使用射线照相和层析成像技术对二元和准二元合金进行化学作图研究，以及x射线荧光成像的最新发展，为更通用的多元素作图技术提供了前景。还考虑了基于同步加速器的化学绘图的未来发展。我们描述了使用射线照相和层析成像技术对二元和准二元合金进行化学作图研究，以及x射线荧光成像的最新发展，为更通用的多元素作图技术提供了前景。还考虑了基于同步加速器的化学绘图的未来发展。