Get access

Effects of interaction volume on X-ray line-scans across an ultrasonically consolidated aluminum/copper interface

Authors

  • Jennifer E. Mueller,

    Corresponding author
    1. Department of Material Science and Engineering, University of Delaware, Newark, Delaware
    2. Center for Composite Materials, University of Delaware, Newark, Delaware
    • Address for reprints: Jennifer E. Mueller, 202 Composites Manufacturing Science Laboratory, University of Delaware, Newark, DE 19716. E-mail: jennifere.mueller@gmail.com

    Search for more papers by this author
  • John W. Gillespie Jr.,

    1. Department of Material Science and Engineering, University of Delaware, Newark, Delaware
    2. Center for Composite Materials, University of Delaware, Newark, Delaware
    3. Department of Civil and Environmental Engineering, University of Delaware, Newark, Delaware
    Search for more papers by this author
  • Suresh G. Advani

    1. Center for Composite Materials, University of Delaware, Newark, Delaware
    2. Department of Mechanical Engineering, University of Delaware, Newark, Delaware
    Search for more papers by this author

  • Contract grant sponsor: Army Research Laboratory; Contract Grant Number: Cooperative Agreement W911NF-06–2-011.

Summary

Diffusion as a bonding mechanism for ultrasonic consolidation of metals is widely debated due to the short weld times and low processing temperatures. To quantify interdiffusion coefficients, X-ray energy dispersive spectroscopy (XEDS) line-scans were performed across an Al–Cu interface using the Scanning Electron Microscope (SEM) with accelerating voltages ranging from 6 to 22 KeV in increments of 2 KeV and a step size of 0.05 microns. Higher accelerating voltages resulted in broader concentration profiles, indicating higher apparent interdiffusion coefficients when scanned at the same location of the same sample. This error due to the interaction volume interference was quantified using Monte Carlo simulations. It was found that an accelerating voltage of 22 KeV and diffusion distance less than 5 microns resulted in at least 50% error. Even at a smaller accelerating voltage of 6 KeV, the percent error in calculation of the interdiffusion coefficient for a diffusion distance of 0.5 microns is expected to be 15–20%. An approximate diffusion distance and apparent interdiffusion coefficient for ultrasonically consolidated Al–Cu were 0.503 microns and 0.013 um2/s, respectively. In this study, a methodology is presented that allows one to estimate the error in the calculation of an interdiffusion coefficient from the accelerating voltage used and the diffusion distance measured by the SEM XEDS at that accelerating voltage. SCANNING 35:327-335, 2013. © 2012 Wiley Periodicals, Inc.

Ancillary