Microstructural and Nanoindentation Studies Across Diffusion-bonded Interfaces in Al/Cu Metal Intermetallic Laminates

In this study, alternate layers of Al and Cu were diffusion bonded to obtain a Metal Intermetallic Laminate (MIL). Intermetallic compounds form at the Al/Cu interface due to in-situ reactions between the metals. The type of compounds formed, their individual mechanical properties and the strength of the interface play a central role in determining the mechanical response of these laminates. In this context, we have characterized the Al/Cu interface and the interfacial intermetallics by means of SEM- based microstructural studies, X-ray diffraction and cross-sectional nanoindentation studies. Microstructural characterization, composition profiles and X-ray diffraction reveal the formation of three intermetallic phases at the interface. Furthermore, nanoindentation studies suggest that the intermetallic phases are not only stiff and hard, but are also well-bound to the abutting metal layers. This suggests the possibility of enhanced mechanical properties for the laminate.