Based on the study of a solid-state reaction process in Al/Ag thin films (the atomic ratio being Al:Ag=1:3) carried out by in situ electron diffraction method and electrical resistivity measurements, the reaction initiation temperature has been determined and a model of structural phase transitions occurring during the solid-state reaction has been proposed. The solid-state reaction begins at 70°C with the formation of an Al-Ag solid solution at the interface of aluminum and silver nanolayers. It has been found that in the reaction process intermetallic compounds γ-Ag2Al => µ-Ag3Al are successively formed. It has been established that for the formation of the µ-Ag3Al phase in thin films (up to 100 nm) the following is necessary: first, significant excess of silver over aluminum in the atomic composition, second, the formation of the µ-Ag3Al phase begins only after all the FCC aluminum has reacted.
The work was supported by the Russian Science Foundation (grant #18-13-00080).