Shock Processing and High Strain Rate Properties of Bulk Metallic Glasses and Their Composites
Final rept. 1 Jul 2005-30 Jun 2008
GEORGIA INST OF TECH ATLANTA SCHOOL OF MATERIALS SCIENCE AND ENGINEERING
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The dynamic mechanical behavior of a Zr-based bulk metallic glass and its composite with tungsten has been investigated to determine the deformation response over a range of stress states, strain rates, and temperatures. The equation of state EOS of the monolithic glass has also bee investigated to determine its phase stability. Anvil-on-rod impact experiments performed on the BMG with and without steel sleeve reveal the deformation, fracture, and elastic-plastic wave propagation response characterized by the Drucker-Prager model. The deformation response of the composite is dominated by the flow and failure characteristics of tungsten. The equation of state experiments performed over a wide range of shock pressure show a polyamorphism transition starting at 26 GPa. The bulk modulus of the high-pressure phase is 144 times that of the ambient pressure phase. Correlation of normalized yield and fracture stress with strain rate shows that the phase transition contributes to a substantial increase in yield and fracture stress at strain rates 10exp 4s, which is more so than that observed for bcc-tungsten and BMG-W composite.
- Properties of Metals and Alloys