通过同步辐射原位高能X射线衍射, 结合差式扫描量热、热重分析、X射线光电子能谱等检测手段, 对具有异常放热现象的铁基非晶合金条带的燃烧机理进行了系统研究。结果表明, 相比不具有异常放热现象、无法自蔓延燃烧的Fe-Nb-B-Y 非晶合金成分, 具有异常放热现象的(Fe_0.72B_0.24Nb_0.04)_95.5Y_4.5非晶条带由于快速晶化放热过程的催化, 能够实现低着火点及自蔓延燃烧。与液-液相变相关联的异常放热现象诱导了升温过程中的快速晶化, 并导致高温下的多步氧化反应。同时液-液相变导致高温氧化阶段的激活能降低, 从而降低反应能垒, 促进高温下的氧化反应。研究表明异常放热现象及其关联的液-液相变对铁基非晶合金的燃烧有“诱导活化”作用。

The functional groups in traditional energetic materials typically contain C, N, and O. These elements are usually unstable and sensitive to external stimuli. Moreover, the chemicals used during the preparation process of traditional energetic materials are toxic and pose many safety and environmental issues. As one of the metastable materials, high-energy-state amorphous alloys are potential candidates for new energetic materials with high combustion heat, low ignition temperature, non-toxicity, and improved safety. In this work, the combustion mechanism of Fe-based amorphous ribbons with an anomalous exothermic phenomenon was systematically studied using in situ synchrotron X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, and X-ray photoelectron spectroscopy. Experimental results show that compared to Fe-Nb-B-Y amorphous alloys with normal thermophysical and combustion behaviors, (Fe_0.72B_0.24Nb_0.04)_95.5Y_4.5 amorphous ribbons with anomalous exothermic phenomena possess low ignition temperature and self-propagating combustion behavior due to the catalysis of the rapid crystallization exothermic process. The anomalous exothermic phenomenon and associated liquid-liquid phase transitions can cause rapid crystallization at elevated temperatures during heating, followed by multi-step oxidation. On the other hand, it was possible to significantly reduce the activation energy of high-temperature oxidation. The liquid-liquid phase transition can lower the energy barrier of the oxidation reaction. In this way, the oxidation reaction at high temperatures can be promoted. The results suggest that the liquid-liquid phase transition has an "induced activation" effect on the combustion of Fe-based amorphous alloys.