(U) Equation of State and Compaction Modeling for CeO2

Fredenburg, David A.¹  Chisolm, Eric D.¹ 

[1]Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

关键词: COMPACTION;    EQUATION OF STATE;    POROUS;   

DOI  :  10.2172/1160104
RP-ID  :  LA-UR-14-28164
PID  :  OSTI ID: 1160104

学科分类：材料科学（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

Recent efforts have focused on developing a solid-liquid and three-phase equation of state (EOS) for CeO₂, while parallel experimental efforts have focused on obtaining high-fidelity Hugoniot measurements on CeO₂ in the porous state. The current work examines the robustness of two CeO₂ SESAME equations of state, a solid-liquid EOS, 96170, and a three-phase EOS, 96171, by validating the EOS against a suite of high-pressure shock compression experiments on initially porous CeO₂. At lower pressures compaction is considered by incorporating a two-term exponential form of the P-compaction model, using three separate definitions for ??(P). Simulations are executed spanning the partially compacted and fully compacted EOS regimes over the pressure range 0.5 - 109 GPa. Comparison of calculated Hugoniot results with those obtained experimentally indicate good agreement for all definitions of ??(P) with both the solid-liquid and three-phase EOS in the low-pressure compaction regime. At higher pressures the three-phase EOS does a better job at predicting the measured Hugoniot response, though at the highest pressures EOS 96171 predicts a less compliant response than is observed experimentally. Measured material velocity profiles of the shock-wave after it has transmitted through the powder are also compared with those simulated using with solid-liquid and three-phase EOS. Profiles lend insight into limits of the current experimental design, as well as the threshold conditions for the shock-induced phase transition in CeO₂.