Microstructure and nanoindentation hardness of Al/Al3Sc multilayers

In the present paper, we discuss the fabrication, characterization and mechanical properties of a unique multilayer system constructed of aluminum and scandium. Thin film deposition techniques have been used to create high-quality polycrystalline multilayered films consisting of inherently soft Al layers (6–100 nm thick) separated by thin (0.5–5 nm) layers of Al3Sc. We use X-ray diffraction, transmission electron microscopy and in situ wafer curvature to characterize the microstructure and intermixing of the Al/Al3Sc multilayer films produced by sputter deposition for this work. The accompanying hardness results show that layering with nanoscale coherent Al3Sc layers increases the hardness by between 200 and 500% over that of a pure aluminum film.