Nanoindentation measurements of the mechanical properties of polycrystalline Au and Ag thin films on silicon substrates: Effects of grain size and film thickness

    Authors

    Y. F. Cao; S. Allameh; D. Nankivil; S. Sethiaraj; T. Otiti;W. Soboyejo

    Comments

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    Abbreviated Journal Title

    Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process.

    Keywords

    nanoindentation; fcc thin films; hardness; Young's modulus; Hall-Petch; effects; thickness effect; SENSING INDENTATION EXPERIMENTS; STRAIN GRADIENT PLASTICITY; ELASTIC-MODULUS; SINGLE-CRYSTALS; CONTACT AREA; DEFORMATION; SURFACES; TEMPERATURE; DEPOSITION; BEHAVIOR; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering

    Abstract

    This paper presents the results of nanoindentation experimental studies of the contact-induced deformation in An and Ag thin films. The paper examines the effects of film thickness and substrate deformation restraint on the mechanical properties of electron beam (e-beam) deposited An and Ag films. Following a brief description of film microstructure, surface topography, and contact-induced pile-up deformation, film mechanical properties (hardness and Young's modulus) were determined using nanoindentation techniques. The indentation size effects (ISE) observed in films with different thicknesses were explained using a mechanism-based strain gradient (MSG) theory. The intrinsic film yield strengths and hardnesses extracted from the MSG theory are shown to exhibit classical Hall-Petch dependence on the inverse square root of the average film grain size. Displacement bursts were also found to occur in Ag films at indentation load levels of 100 mu N. These were attributed to the initial onset of dislocation slip activity, when the shear stress exceeds the estimated theoretical shear strengths of the materials. (c) 2006 Elsevier B.V. All rights reserved.

    Journal Title

    Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing

    Volume

    427

    Issue/Number

    1-2

    Publication Date

    1-1-2006

    Document Type

    Article

    Language

    English

    First Page

    232

    Last Page

    240

    WOS Identifier

    WOS:000239019000030

    ISSN

    0921-5093

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