Unlocking high energy release: Tailored fabrication and combustion mechanisms of spherical Al-B alloy fuels

Metal or nonmetal additives with high-energy-release characteristics are critical energetic materials, such as high-energy solid propellants. This study proposes a prepressing–smelting–ultrasonic atomization technique to fabricate spherical Al-B alloy fuel. The Al-B alloy fuel exhibits a uniform particle size distribution, a smooth surface, and multiple phases, including α-Al, AlB₂, and AlB₁₂. Compared with pure Al powder, the Al-B alloy fuel exhibits a lower oxidation exothermic peak temperature and a higher oxidation weight gain. In combustion diagnostics, the Al-B alloy fuels exhibit enhanced overall energy-release characteristics compared with pure Al. In particular, the maximum combustion heat is increased by approximately 2542 J/g and the maximum flame temperature by approximately 130 K compared with pure Al, whereas the pressurization rates of AlB6 and AlB10 decrease by approximately 62.5% and 85.8%, respectively, accompanied by prolonged pressure durations. These characteristics indicate enhanced total energy release but slower pressure buildup and energy-release kinetics after the incorporation of B. The enhanced heat release is attributed to the synergistic reactions between the alloy components, which induce a distinctive combustion mechanism. Therefore, Al-B alloy fuels exhibit potential for energetic-material applications, such as high-energy solid propellants, where their enhanced overall energy release and prolonged combustion characteristics can be effectively utilized.