Thermokinetic study of intermetallic phase formation in an Al/Cu multilayer thin film system

Abstract

The solid-state reaction process in a multilayer thin film system (Al/Cu)50 has experimentally been studied using the methods of simultaneous thermal analysis (STA) and in situ electron diffraction. A detailed kinetic analysis of the phase formation processes during the solid-state reaction has shown that the observed solid-state transformations can be described by a statistically significant kinetic model where each stage corresponds to the reaction of the n-th order with autocatalysis. The low-temperature stage has been demonstrated to be attributable to the formation of the θ-Al2Cu phase, with the medium-temperature and high-temperature ones corresponding to the α2-AlCu3 and γ1-Al4Cu9 phases, respectively. The kinetic parameters for the formation of the phases θ-Al2Cu, α2-AlCu3 and γ1-Al4Cu9 have been determined. It has been shown that the kinetic model describing the solid-state reaction in the Al–Cu multilayer thin film system is in best agreement with the experimental data in the case of a competition between the formation stages of the α2-AlCu3 and γ1-Al4Cu9 phases.