The subject of reactive phase formation in multilayer thin films of varying periodicity has stimulated much research over the past few years. Recent studies have sought to understand the reactions that occur during the annealing of Ni/Al multilayers. Dark field imaging from transmission electron microscopy (TEM) studies in conjunction with in situ x-ray diffraction measurements, and calorimetry experiments (isothermal and constant heating rate), have yielded new insights into the sequence of phases that occur during annealing and the evolution of their microstructure.In this paper we report on reactive phase formation in sputter-deposited lNi:3Al multilayer thin films with a periodicity A (the combined thickness of an aluminum and nickel layer) from 2.5 to 320 nm. A cross-sectional TEM micrograph of an as-deposited film with a periodicity of 10 nm is shown in figure 1. This image shows diffraction contrast from the Ni grains and occasionally from the Al grains in their respective layers.
