| Abstract Scope |
Driven alloys are intentionally designed to operate far from thermodynamic equilibrium under external stimuli such as irradiation. Unlike conventional materials that accumulate point of line defects, driven alloys exploit irradiation to mitigate damage by forming metastable microstructure states called "steady-states". This typically manifests itself through phase transformations, either induced or accelerated by irradiation balanced by thermal diffusion. In the formation of steady-states, existing interfaces like grain boundaries may exhibit a different behavior in comparison to grain interiors, and can be conceptualized as their own micro-environment.
In this presentation, I will highlight how driven alloys can stabilize metastable or nanostructured configurations, where phase transformations occurring at grain boundaries and interfaces form efficient defect sinks dynamically. These range from radiation-induced precipitation, amorphization, and sequential phase transformations occurring solely at grain boundaries. Supported by quantitative microstructure analysis enabled by correlative techniques in electron microscopy (STEM-EDX, imaging, 4D-STEM), case examples will be presented in dilute binary alloys. Findings will be rationalized in terms of alloy composition and forcing conditions, through the ratio between radiation-induced segregation (RIS) and ballistic mixing at high temperature.
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