SUMMARY
The objective of this work is to evaluate the reaction initiation characteristics of quasi-statically compressed intermetallic-forming aluminum-based reactive materials upon impact initiation, consisting of equi-volumetric tantalum-aluminum, tungsten-aluminum, nickel-aluminum, and pure aluminum. A modified Taylor rod-on-anvil setup was employed to determine the reaction initiation threshold kinetic energy and actual energy for plastic deformation and subsequent reaction. Experimental sample remnants were recovered and examined through X-ray diffraction to determine reaction products. The intermetallic-forming materials were evaluated based on their experimentally determined reaction initiation kinetic energy threshold, as a function of density effects, particle size differences and environmental effects considering both air and vacuum. Multiple experiments were conducted using the 7.62 mm diameter gas gun, while measuring velocity and recovering the products for subsequent X-ray diffraction analysis. The overall results indicate that of the intermetallic-forming system, Ta+Al was the most reactive and was the only system where any reaction products were retrieved. While all of the intermetallic systems reacted in air, only Ta+Al and W+Al reacted in vacuum environments suggesting differences in reaction mechanisms influencing in the reactivity of intermetallic mixtures. Density effects illustrate that higher-density mixtures are more reactive, although the density effect did not directly correlate with ease of reaction in the case of W+Al in comparison with Ta+Al. The effects of differences in constituent yield strength and density on the kinetic energy threshold for reaction initiation were also evaluated. The effect of packing density on the reactivity showed that more densely packed samples react more easily rather than less densely packed samples in the case of pure Al as well as a particle size effect seen in Ni+Al between fine and coarse mesh sizes.