Effects of Li Content and Particle Size on the Thermal Decomposition and Combustion Characteristics of Al–Li Alloys

Abstract

Aluminium-lithium (Al–Li) alloys are crafted by incorporating minute quantities of Li into Al, thereby alleviating the passivation effect of dense alumina. This strategic blend elevates the energy release potential of Al-based fuels by enhancing reactivity and facilitating efficient combustion reactions. The effects of Li content and particle size on the combustion characteristics of Al–Li alloys are systematically investigated, with a particular focus on several pivotal aspects: thermal oxidation behavior, ignition delay time, combustion time, combustion intensity, temperature, and the condensed-phase products. The results show that, upon heating to 1500 °C, the oxidation weight gain of Al–Li alloys reaches 6.5 times that of raw Al. This indicates that adding Li significantly enhances the extent of the oxidation reaction. Increased Li content and particle size reduction further accelerate the oxidation reaction. The ignition delay time and combustion time are effectively shortened, showing a more intense combustion process, higher flame temperature and more significant micro-explosion effect. Ultimately, these factors lead to a significant reduction in the size of condensed-phase products. Based on these insights, a comprehensive impact mechanism for the energy release of Al–Li alloys has been proposed, providing theoretical guidance for applying Al–Li alloys in related fields.

Keywords: Al-Li alloy, Li content, Particle size, thermal decomposition, Combustion mechanism