Effect of reactant and product melting on self-propagating reactions in multilayer foils

The evolution of self-propagating reactions along nanostructured multilayer foils is analyzed computationally. A simplified physical model is used that combines a two-dimensional diffusion equation for the atomic concentration with a quasi-one-dimensional form of the energy equation which accounts for the melting of the reactants and products. The model thus generalizes previous formulations which have ignored melting effects. The computations are used to predict the evolution of self-propagating fronts in Ni/Al foils, and analyze the dependence of these fronts on the foil parameters. In particular, the results indicate that melting substantially affects the properties of the unsteady reactions, and generally results in an appreciable reduction of the average front speed. (C) 2002 American Institute of Physics.