Prof. Timothy P. Weihs
Department of Materials Science and Engineering, Johns Hopkins University
This presentation will cover two topics. The first is nanostructured, metal fuel powders that produce rapid bursts of heat in order to defeat bio-agents such as Anthrax. Ignition thresholds and combustion efficiency can be tuned independently for these metal powders that contain two reactants: elemental Al and Zr or an Al-Mg alloy and elemental Zr. Upon ignition the reactants mix and form intermetallic compounds, rising to temperatures above 1200oC. Once hot the intermetallic particles combust by reacting with both nitrogen and oxygen and reach temperatures near 3000oC. Thresholds for ignition are controlled by changing the average spacing of the reactants within the particles, and combustion efficiency is tuned by varying the diameter and chemistry of the particles. This presentation describes the fabrication, ignition and combustion of these particles as they react in a variety of atmospheres and with iodine oxide particles, drawing on in situ x-ray phase contrast imaging of the combustion process.
The second topic addresses the use of topological optimization methods and 3D textile manufacturing to design and fabricate metallic weaves for a variety of applications that include heat transfer and high-temperature damping. I will describe experimental data demonstrating high permeability and stiffness, superior heat transfer, and novel high-temperature damping. I also will correlate these measurements with model predictions based on the as-fabricated architectures.