Laser-induced spallation of aluminum and Al alloys at strain rates above 2x10{sup 6} s{sup -1}
- Texas Center for High Intensity Laser Science, Department of Physics, University of Texas, Austin, Texas 78712 (United States)
- Stress Engineering Services Inc., Houston, Texas 77041 (United States)
- Department of Mechanical Engineering, University of Texas, Austin, Texas 78712 (United States)
- Z-Backlighter Facility, Sandia National Laboratories, Albuquerque, New Mexico, 87185 (United States)
Material microstructure is a significant determinant of the tensile stress at which materials fail. Using a high-energy laser to drive shocks in thin slabs, we have explored the role material microstructure plays on the spall strength of high-purity and alloyed aluminum at strain rates of (2-7.5)x10{sup 6} s{sup -1}. Slabs of pure recrystallized Al and recrystallized or cold worked Al+3 wt % Mg were shock driven using the Z-Beamlet Laser at Sandia National Laboratories. Velocity interferometer measurements determined the spall strength of the materials, and postshot target analysis explored the microscopic fracture morphology. We observed the greatest spall strength for large-grained, recrystallized high-purity aluminum, with the dominant failure mode being ductile and transgranular. We observe for the first time at these strain rates fracture features for a fine-grained Al+3 wt % Mg that were a combination of brittle intergranular and ductile transgranular fracture types. Postshot analysis of target cross sections and hydrocode simulations indicate that this mixed-mode failure results from spall dynamics occurring on spatial scales on the order of the grain size. Differences in spall strength between these Al samples were experimentally significant and correlate with the damage morphologies observed.
- OSTI ID:
- 21137380
- Journal Information:
- Journal of Applied Physics, Vol. 104, Issue 1; Other Information: DOI: 10.1063/1.2949276; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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