LAUSR

Abstract Aluminum-rich Al-Ti composite powders with controllable particle size distributions were prepared by staged mechanical milling using polar and nonpolar organic process control agents. Staged milling allowed the separation of formation of composites in the first stage from control of particle size and ignition behavior in the second stage. Using the polar solvent acetonitrile in the second stage resulted in more finely dispersed particles with lower onset temperatures for intermetallic formation reactions, and lower ignition temperatures, compared with using the non-polar hexane. All composites showed lower ignition temperatures than reference aluminum. Combustion rates for all composites were greater than for reference aluminum, while net energy release remained comparable. The results suggest that staged milling with process control agents of different polarity is a viable method to control particle size distributions and ignition behavior in mechanically milled, metal-based energetic composite powders while maintaining the energy content. Particle size control is critical for adopting such materials in practical systems.