Dynamic Pressure Induced Transformation Toughening and Strengthening in Bulk Metallic Glasses

The work performed to-date focused on investigation of dynamic pressure induced transformations in simple binary metallic glasses including a Ni80P20 binary alloy in the form of discs cut from an electrodeposited rod made at the Los Alamos National Laboratory, and a Ce75Al25 alloy fabricated via melt spinning at the Ames Laboratory. A Ti-based metallic glass composite was also investigated, in collaborative work with the Jet Propulsion Laboratory, to determine the influence of the in-situ formed crystalline phase on the dynamic compressive and tensile spall strength properties. A number of materials physics and mechanics based fundamental questions were targeted, which required an approach that combines the use of time-resolved impact experiments, with continuum- and molecular-scale simulations. With the availability of our 80-mm and 7.63-mm gas-guns, and the laser-accelerated mini-flyer impact set-up, combined with stress, velocity, and imaging diagnostics, we are able to subject materials to uniaxial-stress loading up to 30 GPa and nano-to-micro-second duration, allowing studies of the influence of stress-states and strain-rates on dynamic deformation and phase transformation over a wide range of loading conditions. The original document contains color images.