Elevated and cryogenic temperature micropillar compression of magnesium–niobium multilayer films

Thomas, K.; Mohanty, G.; Wehrs, J.; Taylor, A. A.; Pathak, S.; Casari, D.; Schwiedrzik, J.; Mara, N.; Spolenak, R.; Michler, J.

Journal of Materials Science 54 (2019)

The mechanical properties of multilayer films consisting of alternating layers of magnesium and niobium are investigated through micropillar compression experiments across a broad range of temperatures. The data collected from the variable temperature micropillar compression tests and strain rate jump tests are used to gain insight into the operative deformation mechanisms within the material. At higher temperatures, diffusion-based deformation mechanisms are shown to determine the plastic behavior of the multilayers. Diffusion occurs more readily along the magnesium–niobium interface than within the bulk, acting as pathway for magnesium diffusion. When individual layer thicknesses are sufficiently small, diffusion can remain the dominant deformation mechanism down to room temperature. Multilayer strengthening models historically rely solely on dislocation-based arguments; therefore, consideration of diffusion-based deformation in nanolaminates with low melting temperature components offers improved understanding of multilayer behavior.