Combustion and energy performance of multiple aluminum-based alloy particles

Abstract

The long ignition delay time, high ignition temperature and agglomeration prevent the aluminum (Al) particles from fully releasing the chemical energy stored within them during combustion. Al-based alloy fuels with high energy density and excellent combustion performance have become a potential candidate for replacement with pure Al. Therefore, understanding the combustion and energy performance of Al-based alloys is beneficial for the development of Al-based energetic materials. Herein, the combustion and energy performance of pure Al and three Al-based alloys were comparatively investigated by means of a thermal analysis system, an ignition and combustion test apparatus, and a variety of physicochemical property characterizations. The results showed that all three Al-based alloys contained at least one intermetallic compound. Al-boron (B) and Al-magnesium (Mg)-B alloys had higher theoretical energy densities than pure Al, while Al-Mg did not. The thermal oxidation properties of all three alloys were significantly better than those of pure Al. Compared with pure Al, the three alloys showed higher burning rate, shorter ignition delays, more vigorous combustion, and higher burnout at room pressure in air. This is still true after adding AP. According to the compositions of the condensed combustion products, the possible chemical reactions during the combustion of the alloys were speculated. Grasping the combustion mechanisms of the alloys is challenging due to the relative lack of thermodynamic data on intermetallic compounds. Finally, a comprehensive comparison of the combustion processes of pure Al and alloys was made. Although the Al-Mg alloy does not have the same theoretical energy density as pure Al, the more outstanding combustion performance and fewer two-phase flow losses may make up for the gap in theoretical energy density.