| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
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| Symposium
|
Progress towards Understanding the Synthesis and Behavior of Metals Far from Equilibrium: A SMD Symposium Honoring Enrique Lavernia on the Occasion of His 60th Birthday
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| Presentation Title |
Amorphization of Covalently-bonded Solids in Laser-induced Shock: A New Deformation Mechanism in Extreme Loading |
| Author(s) |
Marc A. Meyers, Shiteng Zhao, Bruce Remington, Chris Wehrenberg, Hye-Sook Park, Eric Hahn |
| On-Site Speaker (Planned) |
Marc A. Meyers |
| Abstract Scope |
Shock compression subjects materials to a unique regime of high hydrostatic and coupled shear stresses. There are, additionally, an attendant temperature increase and the propagation of a shock front at close to sonic velocity, forcing the agents of plastic deformation in metals to nucleate and propagate dynamically. Covalently bonded materials have, by virtue of the directionality of the bonds, great difficulty in responding to this extreme regime by conventional plastic deformation. Here we propose that shock/shear amorphization observed in Si, Ge, B4C, and SiC is a new deformation mechanism in a broad class of covalently bonded materials. The crystalline structure transforms to a higher-density amorphous one along regions of maximum shear stress, forming nanoscale bands, thereby relaxing the shear component of the imposed shock stress. This process is preceded by the emission and propagation of a critical concentration of stacking faults. Molecular dynamics calculations confirm the new mechanism. |
| Proceedings Inclusion? |
Undecided |