| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Understanding and Predicting Dynamic Behavior of Materials
|
| Presentation Title |
Thermodynamics of Pressure-induced Amorphization in Boron Carbide- Unraveling the Mystery through Molecular Dynamic Simulations |
| Author(s) |
Ghatu Subhash, Amnaya Awasthi, Matthew DeVries |
| On-Site Speaker (Planned) |
Ghatu Subhash |
| Abstract Scope |
In 1994 Grady conducted plate impact experiments on boron carbide and noted its anomalous behavior which he described as “dramatic loss in strength,” “near fluid-like response,” “heterogeneous deformation,” “anomalous volume compression,” and “phase-change-like volume collapse.” Despite more than two decades of research, no convincing explanation is available to unravel this mystery. Through molecular dynamics (MD) simulations of high-pressure compression and shock loading of boron carbide, we draw a link between nanoscale thermodynamics to amorphization. For the first time, we generate Rayleigh lines via MD shock simulations and constructed Hugoniot that confirms to the experimental data. Shock-induced temperature in the ceramic exceeds the melting point causing dramatic loss of strength and near fluid like response leading to amorphization. The anomalous volume compression is reflected in Hugoniot being below the hydrostat. By confirming amorphization to be a thermodynamically driven phenomenon, we resolve the scientific issues pertaining to anomalous behavior of boron carbide. |
| Proceedings Inclusion? |
Undecided |