Characterization of materials under high pressure by combined application of monochromatic and polychromatic X-ray diffraction techniques at HPCAT*

Combining in-situ and in-operando Laue and monochromatic X-ray diffraction techniques with theoretical modelling and ex-situ electron microscopy provides comprehensive experimental information on mechanisms of pressure induced phase transitions and deformation. While Laue diffraction is a powerful tool to observe microstructural changes in single-crystals, X-ray diffraction using monochromatic beam is sensitive to nano-crystalline aggregates with arbitrary crystal orientations and this technique is also widely implemented to solve atomic structures. Recent case studies conducted at the High-Pressure Collaborative Access Team (HPCAT) include mechanism of Si I to Si II phase transition, compression of additively manufactured materials and high entropy alloys, and hcp to bcc transition in Mg. These studies will be used to highlight the power of this technique.