The Weihs Group actively conducts research to design, tune and characterize materials comprised of metals, alloys, oxides, and metal composites for reactions that span a wide range of applications. These include neutralizing harmful toxins or chemical agents (such as sarin) and biological agents (such as anthrax), chemical time delays, non-traditional thermites, and structural reactive materials. The materials are typically nanocomposites with tuned microstructures prepared by high energy mechanical ball milling, magnetron sputtering, swaging or rolling. To aid in understanding the complex reaction mechanisms involved in optimized material performance, we develop novel experimental diagnostics and utilize machine learning algorithms for data mining and tuning material selection.
Ignition and Combustion of Metal Powders

Ignition and Combustion of Metal Powders

This research area aims to understand the fundamental mechanisms and phase transformations governing the ignition and the combustion processes of multi-element composite powders. By varying the chemistry, microstructure, and size of reactive composite powders, we explore how exothermic formation reactions control ignition thresholds and how vapor phase and condensed phase oxidation control the duration and efficiency of combustion. We employ both conventional and novel experimental tools, as well as machine learning to optimize data analysis.
Reactive Materials Research Projects
Structural Reactive Materials

Structural Reactive Materials

This research area aims to understand the fragmentation, breakup, and combustion of structural energetic materials subject to explosive launch or rapid impact in counter-WMD munitions. We examine both model materials and high density materials, focusing on dynamic and quasi-static mechanical properties, as well as energetic release, using state-of-the-art test facilities.
Structural Materials Research Projects Reactive Materials Research Projects
Nucleation within Steep Composition Gradients (Inactive)

Nucleation within Steep Composition Gradients (Inactive)

This DOE project aims to build on our previous work and established capability using nanocalorimeters to study intermetallic formation reactions in the presenence of steep composition gradients. The theory developed in the project will be a notable improvement on our existing understanding of how nucleation occurs in concentration gradients, with the experiments representing the first rigorous and systematic verification of such a model.
Structural Materials Research Projects Reactive Materials Research Projects

Combinatorial Studies of Reactive Materials

The contribution of metal powders to propulsion, blast, and thermobaric effects relies on their ease of ignition and efficiency of combustion. However, there is still limited knowledge of the reactions that occur on the microsecond and millisecond timescales when metal powders ignite and combust in air, as well as the more complex, composite derivatives that arise. Of the metal powders commonly used in energetic formulations, Al and Mg combust primarily in the vapor phase by first evaporating and then oxidizing, while Ti and Zr combust in a condensed liquid or solid phase and are reactive with nitrogen, not just oxygen. We consider this type of reaction to be dual-phase combustion. Combining elements from these two groups can leverage both modes of combustion simultaneously to enhance burn rates and efficiencies for a given powder size.

Reactive Materials Research Projects
Brazing Dissimilar Metals with Novel Composite Foils (Inactive)

Brazing Dissimilar Metals with Novel Composite Foils (Inactive)

This DoE and U.S. Army funded project sought to create and optimize novel reactive foils that are capable of joining dissimilar metals and alloys. Emphasis is placed on creating brazes that are mechanically and chemically robust for a variety of material combinations.
Reactive Materials Research Projects
Environmentally-Friendly Chemical Time Delays (Inactive)

Environmentally-Friendly Chemical Time Delays (Inactive)

This project aims to develop environmentally-friendly chemical time delays, devices that burn over specific times before igniting a downstream pyrotechnic charge. Time delays are widely used in civilian and military pyrotechnics and typically contain hazardous materials. Through novel materials and architectures, we are developing replacement materials which eliminate those environmental hazards while providing comparable and reliable burn times.
Reactive Materials Research Projects