Kinetics of propagating phase transformation in compressed bismuth

Abstract

We observed dynamically driven phase transitions in isentropically compressed bismuth. By changing the stress loading conditions we explored two distinct cases: one in which the experimental signature of the phase transformation corresponds to phase-boundary crossings initiated at both sample interfaces, and another in which the experimental trace is due to a single advancing transformation front in the bulk of the material. We introduce a coupled kinetics - hydrodynamics model that for this second case enables us, under suitable simplifying assumptions, to directly extract characteristic transition times from the experimental measurements.Comment: 7 pages; 3 color figure

Near-equilibrium polymorphic phase transformations in praseodymium under dynamic compression

“…2 and the discussion below. As noted in [12] the dynamic impedance of the window plays an important role in the evolution of the phase transformations inside the sample. This effect is clearly illustrated by the present experiments which, as mentioned above, have been carried out with three types of windows: the "stiff" sapphire window produces a significant pressure enhancement at the interface, "soft" PMMA leads to a pressure drop at the interface, while LiF single crystal, relatively closely dynamically matched to Pr, provides a nearly insitu response.…”

“…A wealth of static high pressure studies have engaged a range of techniques to map the material behavior under compression. While early experimental studies focused on static pressure conditions [5][6][7][8][9] or nearlyinstantaneous shock loading conditions [10], recent developments have enabled explorations on intermediate timescales [11][12][13].…”

High pressure phase transformation in iron under fast compression

“…The applied pressure was independently measured during each experiment by placing a reference probe on the Al panel in the immediate vicinity of the sample. Details of the temperature control system implemented on the Z-accelerator are similar to those described in [9].…”

“…We note that the pressure and temperature of the phase line crossing point as well as the associated volume change depend on the initial sample temperature. Since Fe and Al 2 O 3 are closely matched in their dynamic impedance the measured boundary velocity should reflect the local occurrence of the transformation [9].…”

“…Well known concepts of phase nucleation and growth are being revisited and refined [1][2][3] due to their importance in geophysics, metallurgy, materials science [4][5][6][7] and many other fields, while new experimental techniques, particularly at high pressures, continue to open new vistas of research and exploration [8][9][10][11][12][13][14]. The study of phase transition kinetics under high pressures has a long history, with the earliest reported measurements being performed under static conditions by Bridgman [15].…”