This PhD project will leverage Dynamic TEM (DTEM) to directly visualize irreversible microstructural changes in materials in real time, capturing transformations on timescales ranging from nanoseconds to microseconds with near-atomic spatial resolution. The project will pioneer the direct observation of high-energy ion-induced atomic displacement cascades and the associated ultrafast atomic rearrangements. It will allow progress in the prediction and, eventually, mitigation of their detrimental effect in materials. In addition, it will provide a better understanding of the fundamentals of fast transitions that are able to enhance the glass transition, recrystallization and rejuvenation in amorphous metals. The experiments will reproduce real-world working conditions as closely as possible by integrating temperature, atmosphere, humidity and laser (white light or infrared) illumination. The ion irradiation process will be controlled by tuning parameters such as ion isotope, energy, flux and flow.