Pressure-induced kinetics of the α to ω transition in zirconium

Abstract

Diamond anvil cells (DAC) coupled with x-ray diffraction (XRD) measurements are one of the primary techniques for investigating structural stability of materials at high pressure-temperature (P-T) conditions. DAC-XRD has been predominantly used to resolve structural information at set P-T conditions and, consequently, provides P-T phase diagram information on a broad range of materials. With advances in large scale synchrotron x-ray facilities and corresponding x-ray diagnostic capabilities, it is now becoming possible to perform sub-second time resolved measurements on micron sized DAC samples. As a result, there is an opportunity to gain valuable information about the kinetics of structural phase transformations and extend our understanding of material behavior at high P-T conditions. Using DAC-XRD time resolved measurements, we have investigated the kinetics of the α to ω transformation in zirconium. We observe a clear time and pressure dependence in the martensitic α-ω transition as a function of pressure-jump, i.e., drive pressure. The resulting data are fit using available kinetics models, which can provide further insight into transformation mechanism that influence transformation kinetics. Our results help shed light on the discrepancies observed in previous measurements of the α-ω transition pressure in zirconium.

A Model for Phase Transitions Under Dynamic Compression

“…Time evolution under the master equation leads to k i approaching zero or one asymptotically. This is more consistent with experimental data [18,26] from static compression experiments, and leads to better agreement with dynamic data [9,13,24].…”

In situtransmission electron microscopy study of the thermally induced formation of δ′-ZrO in pure Zr and Zr-based alloy

“…However, there are still some discrepancies in the reported OR between the phase and ! phase, even though much effort has been made over recent decades with a variety of techniques including TEM (Cerreta et al, 2005;Rabinkin et al, 1981), in situ synchrotron diffraction (Yu et al, 2015;Jacobsen et al, 2015;Zong et al, 2014;Wenk et al, 2013), and ab initio modeling (Trinkle et al, 2005(Trinkle et al, , 2003. There are two orientation relationships that have been widely reported.…”

Shear-driven instability in zirconium at high pressure and temperature and its relationship to phase-boundary behaviors

“…It is also possible that the transition region could be influenced by kinetics, as has been demonstrated at ambient temperature previously [49]. From this work, it was determined that the extent of transformation between the two phases was strongly influenced by how rapidly the pressure was changed and by how much.…”