Energy output characteristics of an enhanced aluminized explosive: Impact of Al-Li alloy fuel

Applying new alloy fuels is critical for improving the energy release characteristics of aluminized explosives. Al-Li alloy fuel has become a promising fuel for metallized explosives due to its low ignition temperature, short ignition delay, and fast combustion rate. In this study, three different Al-Li alloy fuels (Li content 2 %, 5 %, and 10 %) were selected to replace pure Al particles, and their effect on oxidation, ignition, and combustion characteristics were examined. Thermogravimetric-differential scanning calorimetry revealed that using Al-Li alloy can cause early oxidation and increase the oxidation rate and weight gain, which is positively correlated with the Li content. Furthermore, the oxygen bomb calorimeter, closed bomb, and laser ignition measurements revealed that adding Li can promote the ignition and combustion of Al and increase its combustion calorific value. Among them, AlLi₁₀ demonstrated the most balanced combination of high combustion calorific value, high combustion intensity, and short ignition delay. Additionally, aging experiments demonstrated that alloy fuels with more Li content are more easily oxidized, which makes it easy to react with HTPB and affects the safety of explosives. The designed HMX/AlLi₂/HTPB explosive samples demonstrated improved detonation heat, detonation velocity, detonation field temperature, and near-field shock wave overpressure of the explosive when using Al-Li alloy fuel due to the ignition and combustion characteristics of Al-Li alloy fuel. Furthermore, the study explained the energy output structure of highly active alloy fuels in metalized explosive systems and proposed a micro-explosion refinement reaction model of Al-Li alloy fuel in the post-detonation combustion zone. The findings of this study may serve to develop AlLi₂ alloy fuel as an attractive candidate for metalized explosives to enhance energy release.