Vapor deposition and characterization of nanocrystalline nanolaminates

Nanolaminates can be: one-dimensional, i.e. an artificial crystal with a composition modulation of amorphous layers; two-dimensional with one component layer crystalline; or three-dimensional wherein all the layers are nanocrystalline. The nanocrystalline nanolaminate can be synthesized through physical vapor deposition methods. Structural characterization includes diffraction from, and imaging of, atomic structure that reveals crystalline phase and lattice distortions. The mechanical properties are dependent upon the specific nanostructural arrangements of atoms at the grain boundaries and within the constituent layers. The deformation behavior of nanocrystalline nanolaminates are shown to be dependent upon dislocation structure, grain boundary, and interlayer distortion effects. Mechanical properties to be reviewed are tensile behavior, and surface nanohardness with accompanying structural characterization through X-ray diffraction and high resolution electron microscopy. The role of layer pair spacing and grain size are now evaluated as measured by tensile strength and surface hardness. It is found that the onset of plastic deformation is most influenced by grain size as compared with layer spacing.