Dynamic Devitrification of Bulk Metallic Glasses (BMGs) and Composites of BMG With Tungsten 5c.

Report No. ARL-TR-3568
Authors: Laszlo J. Kecskes, Robert H. Woodman, and Samuel F. Trevino
Date/Pages: August 2005; 32 pages
Note:
Abstract: The penetration behavior of tungsten-bulk metallic glass (BMG) matrix composites is expected to be strongly influenced by the deformation behavior of the BMG matrix. It has been hypothesized that when the BMC matrix, initially in its viscous, deeply undercooled state, is subjected to compressive loads under the rapid time scales during ballistic impact, it may become a liquid without devitrification. We have carried out a series of in-situ x-ray diffraction experiments at the Advanced Photon Source (APS) and the National Synchrotron Light Source (NSLS) on BMG samples while heating them. At the same time, we carried out differential thermal analysis experiments and analyzed the results using the Kissinger method to estimate the critical heating rates necessary to bypass devitrification. The data collected and results show that the heating rates available at either APS or NSLS were insufficient to verify the hypothesis.
Distribution: Approved for public release
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Last Update / Reviewed: August 1, 2005