Successive phase transitions of tin under shock compression
ABSTRACT Longitudinal and bulk sound velocities of tin in the shock pressure range from ∼25 to ∼80 GPa were measured using a direct reverse-impact method. The bct to bcc phase transition along the Hugoniot was identified by the discontinuity of the longitudinal sound velocity against shock pressure. The incipient melting on the Hugoniot was also revealed by the transition from longitudinal to bulk sound velocity. The shock pressure for bct-bcc phase transition and incipient melting were constrained to be ∼35 and ∼45 GPa , respectively. It is inferred that the bcc phase possesses higher shear modulus than the bct phase.
SourceAvailable from: Jianbo Hu[Show abstract] [Hide abstract]
ABSTRACT: Plate impact experiments in backward-impact geometry were performed on bismuth (Bi) in the pressure range of 11–70 GPa. The bismuth sample used as flyer impacted a LiF window, and the impact velocity and particle velocity at interface were simultaneously measured by a distance interferometer system for any reflector. Hugoniot and sound velocity data were extracted from the observed particle velocity profiles. The obtained plot of shock velocity (D) versus particle velocity (u) showed a discontinuity at u ≈ 0.9 km/s, corresponding to a pressure of ∼27 GPa. Furthermore, plate impact experiments in forward-impact geometry were conducted to measure sound velocities of bismuth. The extracted sound velocity data from backward and forward-impact experiments showed a transition from longitudinal to bulk sound velocity (18 GPa–27 GPa), and the pressure of transition to bulk sound velocity is consistent with the pressure of D-u knee at u ≈ 0.9 km/s. This D-u discontinuity at u ≈ 0.9 km/s is attributed to shock induced melting, and the onset and completion of melting on bismuth Hugoniot are estimated around 18 GPa and 27 GPa, respectively.Journal of Applied Physics 03/2013; 113(9). DOI:10.1063/1.4792755 · 2.19 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: A technique has been developed at the Sandia Z Accelerator using a magnetically driven flyer plate with a double-ramp pulse shape to generate in a test sample a steady shock followed 10–100 ns later by a quasi-isentropic ramped compression wave. Based on velocity data from multiple samples of differing thicknesses, a technique based on backward minimization is presented that allows the determination of material response along an elevated isentrope through the shock state. Data on quasi-isentropically compressed shock-melted tin indicate a stiffer response than currently available equation-of-state models.Applied Physics Letters 06/2013; 102(24). DOI:10.1063/1.4811745 · 3.52 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Results obtained by two methods for the measurement of the sound velocity in tim samples (initial density of 7.28 g/cm3 and impurities less than 0.085%) are presented. In the range of pressures from 30 to 150 GPa, the sound velocity is determined by the overtake method with the use of indicator liquids. The luminescence of the indicator liquids is detected by photodiode-based optical gauges. At shock compression pressures of 5–18 GPa, the sound velocity in tin is measured by the counter release method with the use of manganin-based gauges. The experimental data are compared with numerical predictions and results of other authors. The boundaries of the tin melting region on the shock adiabat are found.Combustion Explosion and Shock Waves 01/2012; 48(1). DOI:10.1134/S0010508212010145 · 0.49 Impact Factor