The role of microstructure refinement in improving the thermal behavior of gas atomized Al-Eu alloy powder

- As active additive, Eu was used in the metal fuel for the first time.
- A novel Al-Eu alloy powder was designed and prepared successfully by the CCGA.
- A special micro-nano structure is found in the Al-Eu alloy powder.
- The thermal behavior of the Al-Eu alloy powder is superior to the pure Al powder.
- The addition of Eu greatly improved the thermal behavior of the pure Al powder.

Europium (Eu) was applied to the metal fuel for the first time in this study. A novel binary alloy powder consisting of Al-97 wt.% and Eu-3 wt.% was designed and prepared successfully by the close-coupled gas atomization. As a result of Eu addition and rapid solidification, a special micro-nano structure is found in the internal of the powder, which was formed by an interlaced distribution consisted of isolated Al phase and Al4Eu phase. It was proved that this special microstructure promoted the oxidation of the Al-Eu alloy powder. The DTA results show that, the oxidation exothermic enthalpy of the Al-Eu alloy powder reached 8108.2 μV·s·mg−1 at the temperature of 1065 °C, which is almost 5 times than that of the pure Al powder. The results of oxidation ratio calculation show that, the oxidation ratios of the Al-Eu alloy powder are both much higher than those of the pure Al powder. The present work indicates that Eu as a novel active additive can be applied to other Al-based alloy powders to improve their thermal behavior.

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