(764e) Aluminum-Based Reactive Materials with Customized Combustion Characteristics

Adding aluminum to propellants, pyrotechnics, and explosives is a common way to boost their energy density. A number of approaches have been investigated that shorten aluminum ignition delay, increase combustion rate, and decrease the tendency of aluminum droplets to agglomerate.  Previous work showed that particles of mechanically alloyed Al-Mg and Al-Ti powders burn faster than similarly sized particles of pure aluminum.  However, preparation of mechanically alloyed powders with particle sizes matching those of fine aluminum used in energetic formulations was not achieved.  This work is focused on preparation of mechanically alloyed and composite Al-Mg and Al-Ti powders in which both internal structures and particle size distributions are adjusted simultaneously.  Milling protocol is optimized for each composition to prepare equiaxial, micron-scale particles suitable for laboratory evaluations of their oxidation, ignition, and combustion characteristics.  Oxidation of the prepared powders is studied using thermo-analytical measurements.  Ignition is characterized experimentally using an electrically heated filament setup.  Combustion is studied using a constant volume explosion setup, for the powder cloud combustion, and a laser ignition setup for characterization of combustion rates and temperatures for individual particles.  For all materials, ignition and combustion characteristics are compared to those of pure Al and compositions with improved performance are identified.  Results will be presented and discussed in this talk.