Formation and effect of intermetallic compounds in the interface of copper/aluminum composites under rolling conditions

Abstract

Rolling and annealing are common composite processes of Copper/Aluminum composites (Cu/Al), but the formation of intermetallic compounds (IMCs) at Cu/Al interfaces and their relationship with processing conditions still lack a nanoscale understanding. Here, we use molecular dynamics (MD) method to simulate the formation of IMCs at Cu/Al interface under different rolling and annealing process parameters with their formation mechanisms quantitatively analyzed. XRD, RDF and potential energy analysis show that rolling promotes the formation of interfacial IMCs, because copper and aluminum atoms tend to diffuse into each other at the interface and combine to form IMCs during rolling. The effects of different size ratios of copper to aluminum and annealing on IMCs are also evaluated. By studying the equivalent phonon thermal conductivity of the interfacial layer and shear strength, it is shown that IMCs enhances interfacial phonon heat transfer, but reduce the interfacial shear strength due to their brittle and hard properties. In addition, the rolling and annealing processes are able to change the dislocation density, thereby affecting the phonon scattering and shear strength of Cu/Al. These results are expected to guide improved directions for the process optimization of high-performance Cu/Al.