laser micro-machined/treated components
Materials Science and Engineering Project

    One of the PM&AM Research team’s greatest strengths is its background in solid-state and
    condensed matter physics. In combination with a strong background in materials science
    and engineering, we can develop new materials and devices, as well as investigate and model
    unknown properties/responses in existing materials. Our current efforts employ Terawatt
    lasers for micro-machining, and to induce damage. We are also developing this technology
    to treat surfaces and create novel interfaces/joins. One of our past programs involved
    drilling Nickel-based alloys (such as Inconel and Hastelloy) with high-energy, ultrashort,
    UV laser pulses. Further overlap with our lasers/optics emphasis occurs in our directed
    energy and remote sensing programs.

    In developing high-performance ceramic armor, as well as potential commercial products,
    we have been collaborating with Professors Wayne Chen and Trudy Kriven to test both
    quasi-static and high-strain-rate properties of transformation-toughened ceramics. This
    work will allow us to better exploit the strength of ceramics, by mitigating their inherent
    brittleness.

    Our current effort is to use Terawatt lasers for micro-machining, and to induce damage. We
    are also developing this technology to treat surfaces and create novel interfaces/joins. One
    of our most recent projects involved drilling Nickel-based alloys (such as Inconel and
    Hastelloy) with high-energy, ultrashort, UV laser pulses. Further overlap with our
    lasers/optics emphasis occurs in our directed energy and remote sensing programs.
In developing high-performance ceramic
armor, as well as potential commercial
products, we have recently been collaborating
with Professors Wayne Chen and Trudy Kriven
to test both quasi-static and high-strain-rate
properties of transformation-toughened
ceramics. This work will allow us to better
exploit the strength of ceramics, by mitigating
their inherent brittleness.
Additional past projects:

  • SOLIDIFICATION
    A major thrust for us has been the experimental, computational, and theoretical investigation of
    solidification, and the accompanying interface kinetics and convective flow. This project has resulted in
    the development of a generalized CELLULAR AUTOMATA SOLIDIFICATION CODE which
    incorporates competing crystalline anisotropies, and has demonstrated the correct behaviour in all of the
    growth regimes, including a cross-over from slow dendrites in the direction to "fast" dendrites in the and
    directions. These dynamics have proven to be key in the recrystallization of the energetic propellant CL-
    20 (China Lake-20, which is of interest primarily to the China Lake Naval Air Warfare Center Weapons
    Division, and Thiokol Propulsion.

  • FABRICATION AND CHARACTERIZATION OF UNSUPPORTED C60/C70 FILMS
    Working together with Professor Don Huffman of the University of Arizona Physics Department , we
    developed a novel method of lifting and holding unsupported films of C60/C70 to allow characterization
    of their various spectra. This work has also led to our interest in using these large molecules to nucleate
    diamond-like thin films in various deposition applications.

  • SUPERCONDUCTORS

  • WHISKER GROWTH
    In certain situations, thin films produce whiskers out of the plane to relieve compressive stresses. We
    have contracted with several industrial partners to help them solve whisker growth problems causing
    failure in critical systems, sensors, and detectors.

  • PLASMA IMMERSION ION IMPLANTATION
    Working in the Plasma Division at Los Alamos National Laboratory we developed a three-axis magnetic
    flux meter, fully encased in ceramic and glass to withstand the harsh environment in the plasma chamber.
    We also developed diagnostics to characterize the growth of oxide and nitride interfaces and the
    associated surface damage.

  • ACOUSTIC AND VIBRATIONAL PROPERTIES OF DISORDERED MATERIALS
  • Working together with Professor John Kieffer of the Materials Science and Engineering Department and
    Materials Research Laboratory at the University of Illinois at Urbana Champaign, we probed different
    disordered materials to determine the effect of the disorder on their vibrational and acoustic modes.
  • The main method was Brillouin scattering, where it was possible to measure the photons that were
    scattered inelastically from the different vibrational modes in the solid. In a perfectly homogeneous
    solid, these modes are phonons which travel at the designated speed of sound. Even in inhomogeneous
    solids, for very low frequency vibrations, the solid looks homogeneous and sustains phonon modes
    traveling at a given effective speed of sound.
  • However, as the phonon wavelengths decrease with increasing frequency and the inhomogeneities
    become more significant, the vibrational modes deviate further and further from phonon states, and
    eventually localize. This was further investigated using the neutron scattering facility at Argonne National
    Laboratory.
  • The primary materials investigated were glass-ceramics and silica aerogels (supplied by the Chemistry
    and Materials Science Division of Lawerence Livermore National Laboratory).
pmamresearch
Materials Science and Engineering Projects