The Equation of State of Al₂O₃: The Building Blocks of a Multiphase Model

We present the basic building blocks on how to construct a multiphase EOS for Al2O3, or sapphire, which plays a pivotal role in both static and dynamic compression research. The EOS foundation is built with well-established thermodynamic models. These models are then parameterized via a Particle Swarm Optimization Method to a variety of experimental data and theoretical calculations. Notably new Hugoniot data from the Z pulsed power facility at SNL enabled us to constrain and validate regions of thermodynamic space not previously tested. In this extreme temperature and extreme pressure region, we compared our predictions from quantum molecular dynamics of a liquid to the measured temperatures from experiment. The work resulted in a new tabular EOS with three solid phases and fluid (gas liquid). New LANL SESAME and LLNL LEOS EOS tables have been generated. This work sets a new benchmark for the development of EoS models of oxides.