Showing papers by "Wendy L. Mao published in 2023"
15 Mar 2023
TL;DR: In this paper , a dynamic diamond anvil cell setup with double-sided laser-heating and in situ X-ray diffraction was used to perform dynamic compression at high temperature and characterize structural transitions.
Abstract: We report on a novel approach to dynamic compression of materials that bridges the gap between previous static- and dynamic- compression techniques, allowing to explore a wide range of pathways in the pressure-temperature space. By combining a dynamic-diamond anvil cell setup with double-sided laser-heating and in situ X-ray diffraction, we are able to perform dynamic compression at high temperature and characterize structural transitions with unprecedented time resolution. Using this method, we investigate the $\gamma-\epsilon$ phase transition of iron under dynamic compression for the first time, reaching compression rates of hundreds of GPa/s and temperatures of 2000 K. Our results demonstrate a distinct response of the $\gamma-\epsilon$ and $\alpha-\epsilon$ transitions to the high compression rates achieved. These findings open up new avenues to study tailored dynamic compression pathways in the pressure-temperature space and highlight the potential of this platform to capture kinetic effects in a diamond anvil cell.
TL;DR: In this article , the phase transitions of iron at high pressure and high temperature conditions using a fastloading dynamic-diamond anvil cell (dDAC) setup were investigated using in situ X-ray-diffraction at the 13-IDD beamline at Advanced Photon Source in Argonne National Laboratory.
Abstract: We investigate the phase transitions of iron at high pressure and high temperature conditions using a fast-loading dynamic-diamond anvil cell (dDAC) setup. Using the dDAC apparatus cou-pled with in situ X-ray-diffraction at the 13-IDD beamline at Advanced Photon Source in Argonne National Laboratory, we demonstrate compression rates of hundreds of GPa/s and monitor the structural evolution with millisecond time resolution. This technique allows us to cover an intermediate compression rate between conventional static- and dynamic-compression experiments, providing new insight on the kinetic effects influencing iron phase transitions. Crucially, the dDAC setup is compatible with doubled sided laser heating, enabling a detailed investigation of the pressure-temperature phase diagram under dynamic compression, as opposed to shock-compression techniques, which are constrained along the Hugoniot curve. We provide thus the first insight on the γ − (cid:15) phase transition ( i.e. , fcc to hcp ) of iron under dynamic loading and compare the results with the trends observed for the α − (cid:15) ( i.e. , bcc to hcp ) phase transition. Our results demonstrate that the specific deformation mechanism strongly influences the response under dynamic loading.