Controlling Material Reactivity Using Architecture

Sullivan, Kyle T.; Zhu, Cheng; Duoss, Eric B.; Gash, Alexander E.; Kolesky, David B.; Kuntz, Joshua D.; Lewis, Jennifer A.; Spadaccini, Christopher M.

doi:10.1002/adma.201504286

Cited by 93 publications

(52 citation statements)

References 26 publications

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“…[23] A similar behavior had previously been seen in porous-Sibased energetic materials. [23] A similar behavior had previously been seen in porous-Sibased energetic materials.…”

supporting

confidence: 70%

“…[5] This has been applied to control mechanical, [6][7][8][9][10] optical, [11][12][13] and electronic [14][15][16] properties of materials, as well as enable new functional materials. [21][22][23][24][25] RMs are a subset of energetic materials and are composites that, upon ignition, give rise to the rapid liberation of energy in the form of heat and/or pressure. [21][22][23][24][25] RMs are a subset of energetic materials and are composites that, upon ignition, give rise to the rapid liberation of energy in the form of heat and/or pressure.…”

Section: D Printed Thermitementioning

confidence: 99%

“…One factor in the choice of these precursors was to pick two systems that could be formulated with similar rheological properties, as disparate rheological properties could lead to potential issues during mixing operations. [21][22][23][24][25] RMs are a subset of energetic materials and are composites that, upon ignition, give rise to the rapid liberation of energy in the form of heat and/or pressure. The rheology of these high solids loaded prethermite inks had to be such that the inks could be extruded through a nozzle (i.e., shear thinning) as wet filaments.…”

mentioning

confidence: 99%

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Development and Characterization of 3D Printable Thermite Component Materials

Durban

Golobic

Bukovsky

et al. 2018

Adv Materials Technologies

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shown that architecture could be used to manipulate the reactivity of aluminum/ copper oxide (Al/CuO) thermites by tailoring the flow of gases and entrained particles using structure. [23] A similar behavior had previously been seen in porous-Sibased energetic materials. [21] This is an exciting result in that it enables one to tailor the energy release rate in such materials without defaulting to the conventional approach of changing the formulation.To further expand upon the previous results, we seek to develop AM formulations which can enable a wide range of architectures to be printed. With this, we can design test articles to further understand and quantify to what extent architecture can be used to control reactivity. However, the direct printing of thermite raises safety concerns since, as-mixed, the materials can lead to a rapid reaction in the event of accidental ignition. A far safer approach would be to formulate the precursor materials separately, and then to directly mix during the printing process.In this work, we formulated an Al and a CuO precursor ink separately. One factor in the choice of these precursors was to pick two systems that could be formulated with similar rheological properties, as disparate rheological properties could lead to potential issues during mixing operations. Al and CuO powder feedstock materials were formulated using micron-sized particles of the materials incorporated into an aqueous hydrogel matrix to render an extrudable prethermite "ink." The rheology of these high solids loaded prethermite inks had to be such that the inks could be extruded through a nozzle (i.e., shear thinning) as wet filaments. The formulation parameters can be seen in Table 1, and some considerations are discussed later in the text. Once formulated, the inks were loaded into a syringe and mounted on the printer. A schematic of the printing setup is shown in Figure 1. The basic components of this setup are highlighted, and include two mounts for syringes, linear extrusion motors, and a precise xyz positioning stage (Aerotech). After extrusion, parts are dried in air and the as-deposited printed filaments retain the properties possessed by the dry powder feedstock material. The formulation and printability of the individual materials are investigated; we subsequently show that the two materials can be mixed on-the-fly to render an ignitable thermite ink.Additive manufacturing (AM) has recently shown great promise as a means to tailor a wide range of material properties, both quasi-static and dynamic. An example of controlling the dynamic behavior is to tailor the chemical energy release rate in composite energetic materials such as thermiteswhich are a subset of pyrotechnics that use a metal fuel and a metal oxide as an oxidizer. Since these materials are most hazardous once finely mixed, the approach taken here is to formulate the fuel and oxidizer separately such that they can be mixed on-the-fly. Herein, the development, formulation, and characterization of two respective aqueous 3D printable in...

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“…[23] A similar behavior had previously been seen in porous-Sibased energetic materials. [23] A similar behavior had previously been seen in porous-Sibased energetic materials.…”

supporting

confidence: 70%

Section: D Printed Thermitementioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Development and Characterization of 3D Printable Thermite Component Materials

Durban

Golobic

Bukovsky

et al. 2018

Adv Materials Technologies

Self Cite

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“…3D printing of energetic materials offers the ability to create advanced design concepts, new complex shapes and structures, execute new operational capabilities, and exert precise spatial control of combustion for advanced munitions (that is, fragmented disassembly)49. As a proof of concept, we created a cylindrical crayon-like structure and a miniature 1:1,260 scale F-22 fighter aircraft or B2 bomber by freeze-casting ∼0.6–1.0 g of nAl@ferritin protein liquid ink in corresponding PDMS moulds (Fig.…”

Section: Resultsmentioning

confidence: 99%

Creation of energetic biothermite inks using ferritin liquid protein

2017

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Energetic liquids function mainly as fuels due to low energy densities and slow combustion kinetics. Consequently, these properties can be significantly increased through the addition of metal nanomaterials such as aluminium. Unfortunately, nanoparticle additives are restricted to low mass fractions in liquids because of increased viscosities and severe particle agglomeration. Nanoscale protein ionic liquids represent multifunctional solvent systems that are well suited to overcoming low mass fractions of nanoparticles, producing stable nanoparticle dispersions and simultaneously offering a source of oxidizing agents for combustion of reactive nanomaterials. Here, we use iron oxide-loaded ferritin proteins to create a stable and highly energetic liquid composed of aluminium nanoparticles and ferritin proteins for printing and forming 3D shapes and structures. In total, this bioenergetic liquid exhibits increased energy output and performance, enhanced dispersion and oxidation stability, lower activation temperatures, and greater processability and functionality.

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“…A high surface-to-mass ratio allows the development of more efficient energy-storage structures (Zhu et al, 2015;Sullivan et al, 2016). Last but not least, a still active major research area involves interaction of electromagnetic waves with periodic structures (meta-materials) (Srivastava, 2016 and many others).…”

Section: Lattice Materials Properties and Range Of Potential Applicationsmentioning

confidence: 99%

Old materials - new capabilities: lattice materials in structural mechanics

Augustyniak

2018

jtam

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Lattice materials (LM) are a novel concept stemming from the combination of crystallography and structural optimisation algorithms. Their practical applications have become real with the advent of versatile additive layer manufacturing (ALM) techniques and the development of dedicated CAD/CAE tools. This work critically reviews one of the major claims concerning LMs, namely their excellent stiffness-to-weight performance. First, a brief literature review of spatially uniform LMs is presented, focusing on specific strength of standard engineering materials as compared with novel structures. An original modelling and optimisation is carried out on a flat panel subject to combined shear and bending load. The calculated generalised specific stiffness is compared against reference values obtained for a uniform panel and the panel subjected to topological optimisation. The monomaterial, a spatially repetitive solution turns out to be poorly suited for stiff, lightweight designs, because of suboptimal material distribution. Spatially non-uniform and locally size-optimised structures perform better. However, its advantage over manufacturable, topologically-optimised conventional designs can at best be marginal (< 10%). Cubic-cell lattices cannot replace conventional bulk materials in the typical engineering use. The multi-cell-type and multi--material lattice structures, albeit beyond the scope of this article, are more promising from the point of view of mechanical properties. The possibility of approaching the linear scaling reported in the recent litterature can make them an attractive option in ultra-low weight designs.

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Controlling Material Reactivity Using Architecture

Cited by 93 publications

References 26 publications

Development and Characterization of 3D Printable Thermite Component Materials

Development and Characterization of 3D Printable Thermite Component Materials

Creation of energetic biothermite inks using ferritin liquid protein

Old materials - new capabilities: lattice materials in structural mechanics

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