Ultrafast Dark-Field X-Ray Microscopy – A New Tool for Analysis of Multiscale Dynamics

Defects and structural distortions dominate the dynamics of metals and functional materials. But many processes – from fracture to phase transitions – have dynamics that rely on multiscale dynamics that are difficult to reconcile between mm-A lengthscales and ms-ps timescales. Dark-field X-ray microscopy (DFXM) can now directly image defects in single- and poly-crystals, resolving distortions deep beneath the surface over a wide field of view, with high sensitivity to strain and inclination in the lattice. We have developed time-resolved DFXM over the past 5 years for multiscale analysis of dynamics, and recently extended this to ultrafast timescales at X-ray free electron lasers. I will present the new DFXM toolbox we have developed and demonstrate how they inform important multiscale structural dynamics relevant to mechanics and thermal engineering. Our DFXM experiments can now collect movies of mesoscale phonon-defect interactions and deformation<i>s in-situ</i> over ms-fs timescales, offering key opportunities to inform models yet untested.