Microstructure and ignition mechanisms of reactive aluminum–zirconium ball milled composite metal powders as a function of particle size

Carbon Fibers Enhance the Propagation of High Loading Nanothermites: In Situ Observation of Microscopic Combustion

“…A major challenge in energetic materials (propellants, explosives, and pyrotechnics) lies in the fine balance among mechanical integrity, energy density, and energy release rate. − Although some energetic materials, such as monomolecular explosives, can release their energy on very small timescales, these reactions are intrinsically limited in energy output based on their fixed stoichiometry and final products. − Other materials, such as metastable intermolecular composites (MICs) or nanothermites, have a potentially higher energy output but react on a much longer timescale. − Interestingly, when mixing the nanothermite with high explosives, the combustion of the nanothermite could induce the transition from deflagration to detonation of a submicron high explosive powder. − The time over which the energy is released is critical to their effective use as a propellant or other niche application of energetic materials.…”

“…Loosely packed energetic powders can propagate from ∼m/s to ∼km/s with propagation velocities closely correlated with the packing density, − but they lack the mechanical integrity necessary for many practical applications. Recent studies on MICs have shown that reducing component size, , enhancing the contact between fuels and oxidizers, − and/or increasing the ignitibility of the fuels − enhance their reactivity. Loose powders must ultimately be manufactured into free-standing architectures by incorporating different types of binders or architectures for any realistic application. − Unfortunately, the incorporation of these energetic materials into dense structures can also inhibit their performance since their combustion becomes limited by binder decomposition and phase transitions, − ultimately leading to order-of-magnitude changes in the burn rate. , This leads to even more parameters to balancebinder materials must be employed to make the materials safe and avoid accidents but must be used in as little quantity as possible to retain their potential energy release. ,− …”

“…Loosely packed energetic powders can propagate from ∼m/s to ∼km/s with propagation velocities closely correlated with the packing density, 5−7 but they lack the mechanical integrity necessary for many practical applications. Recent studies on MICs have shown that reducing component size, 8,9 enhancing the contact between fuels and oxidizers, 10−13 and/or increasing the ignitibility of the fuels 17−19 enhance their reactivity. Loose powders must ultimately be manufactured into free-standing architectures by incorporating different types of binders or architectures for any realistic application.…”

Microstructure and Thermal Deformation Behavior of Hot-Pressing Sintered Zr-6Al-0.1B Alloy

“…First, the three kinds of powder are loaded into a stainless-steel ball mill tank, and several stainless-steel balls are added in ball mill ratio 1:1. Then high purity argon (99.99%) is used to exclude the air in the tank to protect the powder from oxidation and ignition during ball milling [ 32 , 33 ]. The powder mixing time is 30 min at the mixing speed 100 r/min.…”

How Positioning of a Hard Ceramic Tib2 Layer in Al/Cuo Multilayers Can Regulate the Overall Energy Release Behavior

“…For example, ignition temperatures of Al-Zr or Al-Mg binary fuels are significantly lower than those of pure Al of similar sizes due to the exothermic reactions of formation of intermetallic phases (Al+Mg and Al+Zr) that drives the thermite ignition at very low temperatures (~ 350 °C) 34,35 .…”