Study On Preparation And Thermal Performance Of Super-reactive Al-Based Alloy Fuels

In order to overcome problems encountered in the application of pure Al fuel, such as incomplete combustion, low burning rate and high ignition temperature, in this paper, alloying additions on Al have been used to prepare high- reactive Al-based binary and ternary al oy fuels for potential applications in military field.Al-3Li, Al-6Mg and different mass fractions of Al-Mg-Zr alloy fuels were prepared by close-coupled gas atomization(CCGA). The synthesized alloy powders were characterized by XRD, SEM/EDS, TG-DTA and laser particle size analyzer. The results show that the alloy powders are highly spherical in shape and relatively smooth. O xidation behaviors of Al-3Li and Al-6Mg alloys are significantly different. The oxidation of Al-3Li alloy proceeds in only one step and was complete, while the oxidation of Al-6Mg alloy is stepwise and incomplete. The kinetics of the different oxidation events of the two alloys were investigated using K issinger method, the apparent activation energy of the s ingle oxidation step of Al-3Li alloy is 339.7 kJ·mol-1, and the apparent activation energies of the first and second oxidation step of Al-6Mg alloy are 183.7 kJ·mol-1 and 221.2 kJ·mol-1, respectively. Compared with Al-6Mg, Al-3Li presents a lower violent reaction temperature, a larger oxidation reaction rate and a more complete reaction, thus Al-3Li alloy has higher thermal reactivity than Al-6Mg al oy.For Al-Mg-Zr alloys with Mg content ranging from 5% to 30% prepared by CCGA, the oxidation reaction temperature decreases and the multi-step oxidation process transforms into single step oxidation process with increasing of Mg content. The intensive oxidation of Al-20Mg-2Zr and Al-25Mg-2Zr alloys occurs at 945 ? and 938 ? respectively, and the heat release of Al-20Mg-2Zr alloy is the largest. Furthermore, the unique violent reaction of Al-20Mg-2Zr alloy is almost complete, and the activation energy of the reaction is about 250 kJ·mol-1, the frequency factor value is very large. Due to small activation energy and large frequency factor, the alloy is highly reactive and has large oxidation reaction rate at high temperature. Finally, both Al-3Li and Al-20Mg-2Zr are the most reactive alloy fuels, which would become the most promising materials in energetic applications.