Plasticity in cryogenic brittle fracture of ferritic steels: Dislocation versus twinning
Journal article, Peer reviewed
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Original versionMaterials Science & Engineering: A. 2019, 744 335-339. 10.1016/j.msea.2018.12.038
The sub-surface deformation structure after cryogenic (77 K) brittle fracture in a ferritic steel was characterized by scanning electron microscopy (SEM). Twin-like structures were found in many grains below the fracture surface. Electron backscatter diffraction (EBSD) was used to identify the crystallography of the structures, and the twin relation in body-centered cubic (BCC) systems was indexed. The twins in the sub-surface area were characterized further by electron channeling contrast imaging (ECCI). This study clarifies the low temperature brittle fracture behavior in the ferritic Fe-3 wt%Si steel consists of both cleavage and plastic deformation in the form of dislocation activities and twinning.