| Abstract Scope |
Plastic strain localization governs fatigue crack initiation, ductility, and damage evolution in structural alloys, yet quantitative microstructure-based descriptors of localization remain limited. We present recent developments in correlative high-resolution digital image correlation (HR-DIC) and electron backscatter diffraction (EBSD) that enable statistically representative characterization of slip localization from the grain to the sub-grain scale. Using large-area correlative datasets, we extract metrics including slip-band length, intensity, density, interruption frequency, twin-boundary interactions, lattice rotation, geometrically necessary dislocation density, and local crystallographic driving forces. These descriptors reveal how heterogeneous microstructures redistribute plastic deformation through mechanisms such as slip delocalization, cross-slip, and orientation-gradient-induced interruption of long-range glide. Examples from nickel-base superalloys and additively manufactured alloys demonstrate how these quantitative metrics establish direct links between microstructure, deformation mechanisms, and fatigue performance. The proposed framework transforms HR-DIC and EBSD from qualitative characterization tools into quantitative microstructure design methodologies for engineering fatigue-resistant structural materials. |