Solidification and melting of high temperature materials: in situ observations by synchrotron radiation
Solidification and melting of high temperature materials: in situ observations by synchrotron radiation
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DOI：
10.1007/s10853-011-6184-2
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发表时间：
2012-05
影响因子：
4.5
通讯作者：
O. Shuleshova;W. Löser;D. Holland-Moritz;D. Herlach;J. Eckert
中科院分区：
文献类型：
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作者：
O. Shuleshova;W. Löser;D. Holland-Moritz;D. Herlach;J. Eckert
直到最近，了解高温材料的凝固行为，包括许多金属间化合物系统，需要评估大量的个人凝固实验结果。另一个挑战是金属熔体在高温下的反应性。本文综述了近十年来发展起来的高能同步辐射X射线衍射原位观测凝固过程的新方法。在这里，凝固相和转变序列与它们的X射线衍射图案直接相关，这避免了由随后的相变引起的任何混淆，特别是在复杂系统中。通过采用空气动力学、静电和电磁悬浮方法的无容器处理，适用于同步加速器光束线的应用，避免了熔体被杂质污染，这可能会破坏常规方法的凝固研究结果。迄今为止，大部分的研究都集中在亚稳相的形成和过冷熔体的结构。目前的努力液-固相转变的条件下接近平衡，这提供了一个很大的潜力，为收购的相图数据的耐火材料和活性合金，也解决了。
Until recently understanding the solidification behavior of high temperature materials, including many intermetallic systems, required evaluation of a great number of individual solidification experimental results. An additional challenge was the reactivity of metallic melts at elevated temperatures. Alternative methods for in situ observation of solidification processes using the high-energy synchrotron X-ray diffraction, which came up in the last decade, are reviewed in the present work. Here, solidifying phases and transformation sequences are directly related to their X-ray diffraction pattern, which avoids any confusion caused by subsequent phase transformations especially in complex systems. By containerless processing with aerodynamic, electrostatic and electromagnetic levitation methods, adapted to the application at the synchrotron beamline, contamination of the melt with impurities is avoided, which can corrupt the results of solidification studies by conventional methods. To date, the majority of the studies is focused on metastable phase formation and the structure of undercooled melts. Current efforts on liquid–solid phase transformations under conditions close to the equilibrium, which provide a great potential for acquisition of phase diagram data of refractory and reactive alloys, are also addressed.