Interdiffusion of Ni-Al multilayers: A continuum and molecular dynamics study

Xu, Rong-Guang; Falk, Michael L.; Weihs, Timothy P.

doi:10.1063/1.4826527

Cited by 46 publications

(28 citation statements)

References 47 publications

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“…Instead, a slow rate based on diffusion through a solid state product layer should be considered in the dark zones between transverse bands, and a fast rate based on direct dissolution of the refractory element into the liquid state of the fusible element should be considered in the transverse reaction bands themselves. This agrees with recent molecular dynamics simulations performed by Alawieh et al 31 and by Xu et al 32 In their work, Alawieh et al described the temperature-dependent mass diffusivity of Ni/Al nanolaminates, a system similar to the Co/Al laminates studied here. It was shown that there is a significant and discontinuous increase in diffusivity at temperatures below the melting point of Al.…”

Section: Partial Reaction Ahead Of Stalled Reaction Frontssupporting

confidence: 92%

Reaction instabilities in Co/Al nanolaminates due to chemical kinetics variation over micron-scales

Reeves

Adams

2014

Journal of Applied Physics

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The reaction front dynamics of Co/Al reactive nanolaminates were studied as a function of the initial temperature of the unreacted material. Sample geometries that exhibit stable reaction fronts as well as geometries that present “spinning” reaction front instabilities were investigated at initial temperatures ranging from room temperature to 200 °C. It was found that reactions in samples with small reactant periodicities (<66.4 nm) were stable at all temperatures, reaction in large periodicity samples (≥100 nm) were unstable at all temperatures, and reactions in samples with intermediate periodicities transitioned from unstable behavior to stable behavior with increasing initial temperature. The results suggest that behaviors typical of two types of reaction kinetics are present in unstable reaction fronts: slow, diffusion-limited kinetics in the regions between transverse reaction bands, and a faster mechanism at the leading edge of the transverse bands.

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Section: Partial Reaction Ahead Of Stalled Reaction Frontssupporting

confidence: 92%

Reaction instabilities in Co/Al nanolaminates due to chemical kinetics variation over micron-scales

Reeves

Adams

2014

Journal of Applied Physics

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“…Molecular dynamics simulations have contributed to studies of reactive multilayers [179][180][181][182][183]. In particular, MD has been vital for investigating the diffusivity of reactants at high temperatures, information that is not readily available through experiments.…”

Section: Model Descriptions Of Steady Propagating Reactionsmentioning

confidence: 99%

Reactive multilayers fabricated by vapor deposition: A critical review

2015

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a b s t r a c t a r t i c l e i n f o Available online xxxxReactive multilayer thin films are a class of energetic materials that continue to attract attention for use in joining applications and as igniters. Generally composed of two reactants, these heterogeneous solids can be stimulated by an external source to promptly release stored chemical energy in a sudden emission of light and heat. In this critical review article, results from recent investigations of these materials are discussed. Discussion begins with a brief description of the vapor deposition techniques that provide accurate control of layer thickness and film composition. More than 50 reactive film compositions have been reported to date, with most multilayers fabricated by magnetron sputter deposition or electron-beam evaporation. In subsequent sections, we review how multilayer ignition threshold, reaction rate, and total heat are tailored via thin film design. For example, planar multilayers with nanometer-scale periodicity exhibit rapid, self-sustained reactions with wavefront velocities up to 100 m/s. Numeric and analytical models have elucidated many of the fundamental processes that underlie propagating exothermic reactions while demonstrating how reaction rates vary with multilayer design. Recent, time-resolved diffraction and imaging studies have further revealed the phase transformations and the wavefront dynamics associated with propagating chemical reactions. Many reactive multilayers (e.g., Co/Al) form product phases that are consistent with published equilibrium phase diagrams, yet a few systems, such as Pt/Al, develop metastable products. The final section highlights current and emerging applications of reactive multilayers. Examples include reactive Ni(V)/Al and Pd/Al multilayers which have been developed for localized soldering of heat-sensitive components.

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“…Artificially maintaining a constant temperature during reaction in atomistic simulations has resulted in the formation of the B2 (NiAl intermetallic) [25][26][27]. The nucleation of B2, which followed the amorphization of the Al-rich side, was seen to adversely affect the effective diffusion rates [27]. However, the isothermal nature of these simulations do not allow for the study of the interplay between fast reaction kinetics and the formation of the intermetallic phases.…”

Section: Introductionmentioning

confidence: 96%

“…All prior adiabatic simulations failed to observe the formation of intermetallics during reaction. Artificially maintaining a constant temperature during reaction in atomistic simulations has resulted in the formation of the B2 (NiAl intermetallic) [25][26][27]. The nucleation of B2, which followed the amorphization of the Al-rich side, was seen to adversely affect the effective diffusion rates [27].…”

Section: Introductionmentioning

confidence: 97%