Microstructural study of an oscillatory formation reaction in nanostructured reactive multilayer foils

Abstract

We report evidence of an oscillatory formation reaction in nanostructured Zr∕Al∕(CuNi) reactive multilayer foils. The oscillations create periodic ripples on the surface of the foil as well as periodic variations in the length scale of the microstructure of the reacted foil. We describe the nature of the resulting microstructure, and relate this to superadiabatic temperature oscillations at the reaction front. We also examine the effect of ambient temperature on the magnitude and period of the oscillations, and compare the results to numerical predictions and to experimental data for other reactive systems.

Combustion of heterogeneous nanostructural systems (Review)

“…The roughness of the reactive layers and the inhomogeneity of their composition enhance the amplitude of oscillations. These results agree with experimental observations of the oscillatory combustion mode in Ti/Al nanofilms [99] and also the traces of self-induced oscillations in combustion products of Zr/Al/(CuNi) [128] and Ti/Al [129] films.…”

“…A detailed analysis, however, shows that this is not so. First of all, to obtain the calculated burning rates that coincide with experimental measurements, the authors of the theoretical papers [127][128][129][130][131][132] have to use strongly overestimated values of the diffusion coefficients (sometimes, by several orders of magnitude). The validity of these assumptions is not obvious.…”

Reactive multilayers fabricated by vapor deposition: A critical review

“…In each of these geometries, one or more substrates are moved between two, high-purity vapor sources and rotated to improve uniformity, if needed. Advanced sputter deposition systems afford complex multilayer designs such as those with graded-layer periodicity [69], dual periodicity [70], and more than two reactant species [71,72]. Non-planar multilayers have been fabricated on curved substrates [73,74].…”

Quantifying transient states in materials with the dynamic transmission electron microscope

“…The application of a localized source of heat initiates mixing and energy release that creates a selfpropagating reaction front that propagates throughout the material, releasing heat to the surroundings. RMLF have found application in material joining and other localized heat source applications [43][44][45][46][47][48]. One typical system that is used is alternating layers of Al and Ni that when heated will mix and form an intermetallic phase(s) that depends on the overall atomic composition.…”