Probing phase transitions at intermediate compression rates using time-resolved X-ray diagnostics

Fast compression using dynamic diamond anvil cells (dDACs) allows for the study of materials at intermediate strain rates that are not accessible using traditional static and dynamic compression techniques. These devices utilize piezo actuators to achieve compression timescales ranging from ~1 ms to several minutes, allowing for the study of phase transition kinetics at compression rates spanning over 7 orders of magnitude (~10^-2-10^5 GPa/s). Characterization of material behavior under dynamic compression requires time-resolved diagnostics compatible with the compression timescale. X-ray diffraction measurements at synchrotron sources provide structural information at kHz repetition rates, while X-ray phase contrast imaging allows for the visualization of samples as they undergo structural phase transitions such as melting and crystallization. More recently, the implementation of the dDAC at the European X-ray Free Electron Laser (EuXFEL) has allowed for structural studies to be extended to µs timescales. In this talk, I will discuss how these recent developments have allowed for the study of pressure-induced structural transitions in a range of different elemental materials, paving the way for future studies of phase transition kinetics at previously inaccessible compression rates.