Effect of varying bilayer spacing distribution on reaction heat and velocity in reactive Al/Ni multilayers

Journal Article · Wed Apr 15 04:00:00 EDT 2009 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3087490· OSTI ID:21356103

Knepper, Robert; Fritz, Greg; Fisher, Kaitlynn; Weihs, Timothy P ^[1]; Snyder, Murray R ^[2]; Knio, Omar M ^[3]

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1. Department of Materials Science and Engineering, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218 (United States)
2. Department of Mechanical Engineering, United States Naval Academy, 121 Blake Rd., MS 11C, Annapolis, Maryland 21402 (United States)
3. Department of Mechanical Engineering, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218 (United States)

Self-propagating reactions in Al/Ni nanostructured multilayer foils are examined both experimentally and computationally to determine the impact of variations in reactant spacing on reaction properties. Heats of reaction and reaction velocities have been characterized as a function of average bilayer spacing for sputter-deposited, single-bilayer foils (having a uniform bilayer spacing) and for dual-bilayer foils (having two different bilayer spacings that are labeled thick and thin). In the latter case, the spatial distribution of the thick and thin bilayers is found to have a significant effect on reaction velocity, with coarse distributions leading to much higher reaction velocities than fine distributions. Numerical simulations of reaction velocity match experimental data well for most spatial distributions, with the exception of very coarse distributions or distributions containing very small bilayer spacings. A simple model based on thermal diffusivities and reaction velocities is proposed to predict when the spatial distribution of thick and thin bilayers becomes coarse enough to affect reaction velocity. This combination of experiment and simulation will allow for more effective design and prediction of reaction velocities in both sputter-deposited and mechanically processed reactive materials with variable reactant spacings.

• OSTI ID: 21356103
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 105; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
ALUMINIUM
COMPUTERIZED SIMULATION
DEPOSITION
DISTRIBUTION
ELEMENTS
ENTHALPY
FOILS
KINETICS
LAYERS
MATHEMATICS
METALS
NANOSTRUCTURES
NICKEL
NUMERICAL ANALYSIS
PHYSICAL PROPERTIES
REACTION HEAT
REACTION KINETICS
SIMULATION
SPATIAL DISTRIBUTION
SPUTTERING
THERMAL DIFFUSIVITY
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENTS