Femtosecond Laser-Assisted Health Monitoring of Critical Structural Components in Advanced Defense Systems |
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Collaborators: S. Yalisove, J.W. Jones, J. Nees, J. Whitaker, and G. Mourou, Universiy of Michigan
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Materials:
Metals
Application: Structural Technique: Processing |
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Remarkable advances in ultrahigh-intensity lasers as sources of hyperspectral radiation offer unprecedented opportunities for probing and modifying the structure of advanced engineering materials. The objective of this MURI program is to develop the scientific basis for use of ultrafast lasers as materials diagnostics and microfabrication tools for advanced aircraft engine materials and components. This new frontier of materials diagnostics is possible due to the extreme fields that drive relativistic interaction with matter on unprecedented timescales, enabling a range of multispectral characterization approaches. In the plasma interaction between a focused relativistic intensity laser pulse and a solid material, a micron-sized source of radiation delivers sub-picosecond bursts of partially coherent x-rays that can be utilized for analysis by absorption, fluorescence, and diffraction. Additionally, time-resolved electron and x-ray imaging of laser-induced acoustic waves offer significant potential for analysis of dislocation dynamics and crack growth, issues that underlie damage and failure of components. Laser-Induced Breakdown Spectroscopy (LIBS) can be combined with other analysis techniques for simultaneous chemical analysis. Ultrafast double-pulse LIBS, with a higher signal-to-noise ratio than other LIBS techniques, has the advantage of reproducibly ablating only nanometers of material, leaving negligible collateral damage and making this technique effectively non-destructive. The absence of collateral damage with ultrashort pulses also enables new approaches to machining, repair and creation of simulated flaws for advancement of life prediction methodologies. Finally, ultrafast lasers can uniquely create, receive, and apply pulses of millimeter- and submillimeter-wavelength broadband radiation (THz pulses) in order to devise advanced diagnostics for complex, multilayered materials. These techniques will collectively enable the acquisition of structural and chemical information in a non-destructive mode at standoff distances in ambient or inert gas environments with no need for specialized chambers. In this program we will use the turbine blade as a vehicle for demonstrating the potential benefits of a hyperspectral diagnostic and materials modification platform. The program consists of several interrelated projects, each coupling an ultrafast technique with investigation of one or more classes of material flaws and is a multidisciplinary collaboration between the Center for Ultrafast Optical Sciences, Materials Science and Engineering and the Physics Department at the University of Michigan. |
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Materials Science and Engineering, University of Michigan
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- Femtosecond Laser-Assisted Health Monitoring of Critical Structural Components in Advanced Defense Systems
| P.I.: | Tresa Pollock |
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| Sponsor: | DARPA |