In this area, we study the fundamental properties of structural reactive materials that enhance and alter the total and rate of energy released during high-rate impact conditions.  Under impact, excess strain builds up at the interface between the reactive components, which leads to asperities or hot spots that can lead to an autocatalytic combustion process.  By manipulating the topology and morphology of the precursors in the reactive material, significant changes can be imparted to the sensitivity of the material when it is initiated.  Our experiments entail studying the coupled effects of slight changes in the precursor composition and the level of their intermixing on hot-spot initiation characteristics.  We quantify their quasi-static and high-strain-rate behavior under controlled loading conditions that include both compression and shear.  Thermal analysis of representative samples, coupled with post-mortem examination of recovered fragments provide insight into the relationships between the rate of ignition and number of hot spots.

In this area, we study fundamental processes that occur during laser and electron powder bed fusion processes, two widely used additive manufacturing methods, of refractory metals and alloys.  After designing the alloy chemistry, our investigations look at improving the role of process variables that lead to improved and finer-scale control of the microstructure and the resultant mechanical properties.  In particular, we vary the rate of heating and cooling by altering the energy being deposited into the material, and the subsequent cooling rate to temper and mitigate the build-up of residual stresses that would otherwise lead to a degradation of key structural properties.  Additionally, we control ambient conditions such as the base temperature of the build and/or the level of impurities, e.g., oxygen, during the build process to alter the product properties.  These properties are determined via the examination of the morphology, texture, and mechanical behavior.