Plasticity, localization, and damage in ferritic-pearlitic steel studied by nanoscale digital image correlation

The evolution of deformation from plasticity to localization damage is investigated in ferritic-pearlitic steel through nanometer-resolution microstructure-correlated SEM-DIC (µ-DIC) strain mapping, enabled highly accurate microstructure-to-strain alignment. We reveal the key mechanisms ferrite and pearlite as well their into relation microstructural arrangement. Notably, two contrasting were identified that control whether initiation occurs and, connection hotspots grains, potentially results macroscale fracture: (i) cracking bridges with relatively clean lamellar structure by brittle fracture cementite lamellae due build-up concentrations nearby ferrite, versus (ii) large without a more “open”, chaotic morphology, which enables plastic percolation paths interlamellar channels. Based on these insights, recommendations for resistant steels are proposed.