Phase transformation in boron under shock compression

Abstract

Using first-principles molecular dynamics, we calculated the equation of state and shock Hugoniot of various boron phases. We find a large mismatch between Hugoniots based on existing knowledge of the equilibrium phase diagram and those measured by shock experiments, which could be reconciled if the $\alpha$-B${}_{12}$/$\beta \to \gamma$-B${}_{28}$ transition is significantly over-pressurized in boron under shock compression. Our results also indicate that there exists an anomaly and negative Clapeyron slope along the melting curve of boron at 100 GPa and 1500--3000 Kelvin. These results enable in-depth understanding of matter under shock compression, in particular the significance of compression-rate dependence of phase transitions and kinetic effects in experimental measurements.

arXiv comment18 pages, 5 figures (1 in graphical abstract)

References in corpus (7)

• Ionic high-pressure form of elemental boron
• Phase relations in boron at pressure up to 18 GPa and temperature up to 2200 °C
• Pre-melting hcp to bcc Transition in Beryllium
• Equation of state of warm-dense boron nitride combining computation, modeling, and experiment
• Comparison of solid state crystallization of boron polymorphs at ambient and high pressures
• Theoretical and experimental investigation of the equation of state of boron plasmas
• First non-icosahedral boron allotrope synthesized at high pressure and high temperature

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