Dynamic Experiments To Study The Alpha-Epsilon Phase Transition In Cerium

The ability to understand and predict the response of matter at extreme conditions requires knowledge of a material's equation-of-state including the location of phase boundaries, transition kinetics, and the evolution of material strength. Cerium is a material with a complex phase diagram that continues to attract significant scientific interest. Recent dynamic experiments have provided information on the low-pressure gamma-alpha phase transition, sound speed, and Hugoniot data for the higher-pressure alpha phase, as well as the incipient shock melt transition. Despite these efforts, there are still regions of the phase diagram that are largely unexplored dynamically, including the high-pressure region below the melt boundary. Along a room temperature isotherm, diamond anvil cell data report a transition to the epsilon phase between 13 and 17 GPa. At higher temperatures, similar diamond anvil cell data show significant disagreement regarding the existence, location, and slope of the epsilon-phase boundary. In this work, double-shock loading was used to access the alpha-epsilon region of the phase diagram to obtain equation-of-state information and to determine the location of the epsilon-phase boundary for shock loading. (c) 2020 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).