In-situ assembly of Al-Li-Si alloy powders with enhanced thermal stability and tailored combustion

Abstract

Aluminum (Al)-lithium (Li) alloys are ambitious candidates for application in energetic materials, however, the high reactivity of Al-Li compound and Li in alloys affects their thermal stability, which results in gradually lower active content and diminished performance, impeding their further application in energetics. In this study, the specific content of silicon (Si) was introduced into Al-Li alloy via the centrifugal atomization that allows in-situ assembly of Al, Li, and Si at the single particle level, thus resulting in more stable Al-Li-Si compounds instead of active Al-Li compounds and Li and enhancing their thermal stability. The results show that Al-Li-Si alloy powders are in a high degree of sphericity, which are composed of αAl and AlLiSi. Compared to Al-Li alloys, Al-Li-Si alloys initiate the oxidization at a higher temperature (∼600 ℃) since the existence of more stable Al-Li-Si compounds than Li in Al-Li alloys, which indicates a higher thermal stability. Al-Li-Si alloys also show high heat release and combustion efficiency similar to Al-Li alloys. In the meanwhile, Al-Li-Si alloy-based composites maintain almost the same combustion properties compared to Al-Li/PTFE energetics, along with prolonged combustion duration. Therefore, Al-Li-Si alloy powders are promising candidates for application in energetic materials considering their higher thermal stability and tunable combustion properties.