Gold-Nickel Multilayer Films: Structure-Property Correlations

Abstract

Gold-nickel multilayer films with periods of 1.2 - 4.6 nm were deposited on silicon substrates by magnetron sputtering, and plan and cross-sectional specimens were examined by transmission electron microscopy. The cross-sectional specimens revealed well-defined layering and columnar growth features that extended through the film thickness. Dark striations extending normal to the layers were attributed to diffraction contrast from defect strain fields. Diffraction patterns showed that the films were highly textured and that short-period films had a single fcc structure, while long-period films separated into three fcc structures. High-resolution images of the layer interfaces showed local regions of epitaxy partitioned by regions of disorder.Indentation tests using a Nanoindenter, a depth-sensing indentation device, were performed to measure the elastic modulus and hardness of the films. No modulus enhancement was detected, and a small variation in hardness was measured.

Analysis of Strain Relaxation in Au/Ni Multilayers by X-Ray Diffraction

“…In the previous study, a kinematical x-ray diffraction model, as proposed by Speriosu [7,8], was used successfully to analyze the microstructures of Au/Ni metallic superlattices [9]. In the present study, an attempt was made to correlate the supermodulus effect present in the Au/Ni system with the strain distribution obtained from this kinematic model.…”

Mechanical properties of materials with nanometer scale microstructures. Progress report, 1 April 1989 to Present

“…The supermodulus effect has been reported as an anomalous increase of as much as several hundred percent in the elastic moduli of compositionally-modulated films in a narrow range of modulation wavelength [ 1,2,3,4,5,6]. Figure 1 shows a typical result taken from Yang et al for (111) Au/Ni films tested in a bulge tester.…”

“…In a thin-walled pressure vessel the stresses and strains are everywhere the same, whereas in a bulge test the circumferential strain at the edge must be zero due to the clamping constraint. This discrepancy, along with large variations in reported test results from the same material [ 1,14], prompted us to examine the models used to analyze deformation behavior in bulge tests; we accomplished this through the use of the finite element method.…”