Research on the Application of Aluminum-lithium Alloy in HTPB Propellant

To address the issue of incomplete combustion of aluminum powder in hydroxyl-terminated polybutadiene (HTPB) propellant, the combustion efficiency of fuel is improved to enhance the specific impulse of engine by replacing aluminum powder with aluminum-lithium alloy. The particle size, morphology, phase and hardness of aluminum-lithium alloy are characterized by using instruments such as laser particle size analyzer and scanning electron microscope, and its oxidation and ignition characteristics are tested by using simultaneous thermal analyzer and closed ignition device. HTPB propellant is prepared using the casting method to study the impact of aluminum-lithium alloy on the comprehensive properties of HTPB propellant, including processing performance, safety performance, combustion performance, and mechanical properties. Ignition test is also conducted on HTPB propellant. Experimental results indicate that the aluminum-lithium alloy particles have a smooth surface with a sphericity of 0.92, an ignition temperature of approximately 870°C, a maximum combustion calorific value of 29.92 kJ/g, and a combustion efficiency of 96.89%. After replacing aluminum powder with aluminum-lithium alloy, the friction sensitivity of HTPB propellant is increased, while the combustion heat and combustion rate are improved. Other properties are basically the same as those of the reference formulation. Ground ignition test results demonstrate that the introduction of aluminum-lithium alloy increases the measured specific impulse of the propellant by 2 s, indicating a significant energy enhancement effect. Overall, aluminum-lithium alloy can be used to improve the combustion efficiency and specific impulse of HTPB propellant, making it an ideal candidate material to replace micron-sized aluminum powder as a solid-phase fuel.