Amorphous Ni/Al nanoscale laminates as high-energy intermolecular reactive composites

Vishnu, Karthik Guda; Cherukara, Mathew J.; Kim, Hojin; Strachan, Alejandro

doi:10.1103/physrevb.85.184206

Cited by 17 publications

(14 citation statements)

References 29 publications

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“…This indicates that the reactions are controlled by mass diffusion and exhibit universal behavior. 23 While the exponents remain relatively constant for all defect-free laminates (independent of temperature and interface orientation) the effective diffusion constant depends on the conditions of the simulation. For each temperature and crystallographic orientation we extract the effective diffusion constant by fitting the λ 2 vs τ MD data to Eq.…”

Section: B Reaction Time Scales and Role Of Nanostructurementioning

confidence: 99%

Role of nanostructure on reaction and transport in Ni/Al intermolecular reactive composites

2012

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We use molecular dynamics to characterize the exothermic chemistry of Ni/Al nanolaminates for various temperatures, periodic lengths, and in the presence of extended defects. We show that the reaction is mass diffusion controlled for bulk nanolaminates, with the overall reaction time scaling with the square of the mean transport distance. The presence of voids or free surfaces not only leads to a significant decrease in reaction time (by as much as a factor of 5), but fundamentally changes the nature of the reaction. Free surfaces and voids running across several periods provide a mechanism for ballistic mass transport and change the scaling between reaction time and characteristic transport distance.

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Section: B Reaction Time Scales and Role Of Nanostructurementioning

confidence: 99%

Role of nanostructure on reaction and transport in Ni/Al intermolecular reactive composites

2012

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“…1-8 Especially, those composed of an Al core and a metallic shell have received intensive interest recently due to their practical significance in producing the highefficiency energetic nanomaterial. [3][4][5][6][7][8] Nanoparticles have interesting physical properties, including enhanced reactivity 9 due to the high surface area to volume ratio. With that in mind, nanoparticles may provide larger energy release rates for explosive and propellant reactions.…”

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confidence: 99%

Molecular dynamics simulations on the melting, crystallization, and energetic reaction behaviors of Al/Cu core-shell nanoparticles

Cheng¹,

Zhang²,

Zhang³

et al. 2013

Journal of Applied Physics

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Using molecular dynamics simulations combined with the embedded atom method potential, we investigate the heating, cooling, and energetic reacting of core-shell structured Al-Cu nanoparticles. The thermodynamic properties and structure evolution during continuous heating and cooling processes are also investigated through the characterization of the total potential energy distribution, mean-square-distance and radial distribution function. Some behaviors related to nanometer scale Cu/Al functional particles are derived that two-way diffusion of Al and Cu atoms, glass phase formation for the fast cooling rate, and the crystal phase formation for the low cooling rate. Two-way atomic diffusion occurs first and causes the melting and alloying. In the final alloying structure, Cu and Al atoms mixed very well except for the outmost shell which has more Al atoms. For the investigation of the thermal stability and energetic reaction properties, our study show that a localized alloying reaction between the Al core and Cu shell is very slow when the initial temperature is lower than 600 K. But a two-stage reaction may occur when the initial temperature is 700 K. The reaction rate is determined by the solid-state diffusion of Al atoms in the Cu shell at the first stage, yet the reaction rate is much faster at the second stage, due to the alloying reaction between the liquid Al core and the Cu shell. At higher temperatures such as 800 K and 900 K, the alloying reaction occurs directly between the liquid Al core and the Cu shell.

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“…On the other hand, there are very interesting studies of shock waves in AlNi multilayer materials [10][11][12][13][14][15]. They reveal exothermic reactions and alloying of the multilayer systems under shock wave treatment.…”

Section: Introductionmentioning

confidence: 98%

Laser ablation of Al–Ni alloys and multilayers

et al. 2016

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Laser ablation of Al-Ni alloys and multilayers has been studied by molecular dynamics simulations. The method was combined with a two-temperature model to describe the interaction between the laser beam, the electrons, and the atoms. As a first step, electronic parameters for the alloys had to be found and the model developed originally for pure metals had to be generalized to multilayers. The modifications were verified by computing melting depths and ablation thresholds for pure Al and Ni.Here known data could be reproduced. The improved model was applied to the alloys Al 3 Ni, AlNi and AlNi 3 . While melting depths and ablation thresholds for AlNi behave unspectacular, sharp drops at high fluences are observed for Al 3 Ni and AlNi 3 . In both cases, the reason is a change in ablation mechanism from phase explosion to vaporization. Furthermore, a phase transition occurs in Al 3 Ni. Finally, Al layers of various thicknesses on a Ni substrate have been simulated. Above threshold, 8 nm Al films are ablated as a whole while 24 nm Al films are only partially removed. Below threshold, alloying with a mixture gradient has been observed in the thin layer system.

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Amorphous Ni/Al nanoscale laminates as high-energy intermolecular reactive composites

Cited by 17 publications

References 29 publications

Role of nanostructure on reaction and transport in Ni/Al intermolecular reactive composites

Role of nanostructure on reaction and transport in Ni/Al intermolecular reactive composites

Molecular dynamics simulations on the melting, crystallization, and energetic reaction behaviors of Al/Cu core-shell nanoparticles

Laser ablation of Al–Ni alloys and multilayers

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