Microstructural characterization and strengthening mechanism of AlN/Y nanocomposite and nanomultilayered films.

The AlN/Y nanocomposite and nanomultilayered films with different Y contents were fabricated by the magnetron sputtering technique. The microstructures and mechanical properties of the AlN/Y nanocomposite and nanomultilayered films were characterized and measured, respectively. The AlN/Y nanocomposite film is composed of equiaxed AlN nanocrystallites encapsulated by the Y interfaces. When the Y:Al ratio is 2:23, Y interfaces can exist as the crystallized state and keep the epitaxial growth with the adjacent AlN nanocrystallites. Accordingly, the crystallization degree and mechanical properties are improved. The AlN/Y nanomultilayered film consists of the evident multilayered structure with distinct interfaces. When the Y-layer thickness is no more than 0.7 nm, Y layers are inclined to grow epitaxially with the adjacent AlN layers, leading to the improvement of crystallization degrees and mechanical properties. The interfacial evolutions and mechanical properties variations between AlN/Y nanocomposite and nanomultilayered films have the common feature as the Y content grows. It has been experimentally and theoretically verified that the AlN/Y nanocomposite and nanomultilayered films have the same coherent-interface strengthening mechanism. [ABSTRACT FROM AUTHOR]