New model for the shock-induced. alpha. -quartz r arrow stishovite phase transition in silica
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
A new model has been developed to describe the {alpha}-quartz to stishovite phase transition in silica under shock-loading conditions. During hydrodynamic simulations, individual global equations of state for the {alpha}-quartz and stishovite phases of silica are mixed in accordance with process-dependent constraints on the Gibbs free energy difference between the phases ({Delta}{ital G}). For the shock-induced transition, {Delta}{ital G} is required to equal a simple two parameter function of the mass fraction of stishovite. Unlike previous models, the new constraint equation assumes that the shock induced phase transition begins at the equilibrium phase boundary, but is not completed unless peak stresses on the order of 40 GPa are achieved. On release, the reverse transition is required to satisfy the usual thermodynamic equilibrium condition ({Delta}{ital G}=0). It is shown that hydrodynamic simulations combining this hysteretic phase transition model with a strength model that assumes partial softening after yielding are capable of reproducing experimental Hugoniot and release data for crystalline silica in the mixed-phase region.
- OSTI ID:
- 6958703
- Journal Information:
- Journal of Applied Physics; (United States), Journal Name: Journal of Applied Physics; (United States) Vol. 72:11; ISSN 0021-8979; ISSN JAPIA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360602* -- Other Materials-- Structure & Phase Studies
58 GEOSCIENCES
580000 -- Geosciences
CHALCOGENIDES
EQUATIONS
EQUATIONS OF STATE
EXPLOSIONS
MINERALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PRESSURE DEPENDENCE
SHOCK WAVES
SILICON COMPOUNDS
SILICON OXIDES
SIMULATION
STISHOVITE
UNDERGROUND EXPLOSIONS
VERY HIGH PRESSURE