Investigation of the relation between bainitic-ferritic microstructures and coincidence-site lattice boundaries by electron backscatter diffraction

摘要

Both bainitic-ferritic (BF) microstructures and coincidence-site lattice (CSL) boundaries are believed to be crucial for mechanical strength and corrosion resistance of steels, but little knowledge has been obtained about the relation between them. The present work systematically studied bainitic-ferritic microstructures and boundaries, with the emphasis on the relation between them by the five-parameter characterization method using the electron backscatter diffraction (EBSD). The results show that transformation from austenite to bainite leads to a hierarchical microstructure, where a preferable combination of bainitic variants form on the same habit plane and directions in the Kurdjumov-Sachs (K-S) relation. Misorientations of the hierarchical BF microstructure exibit a featured distribution with an obvious aggregation around 60 degrees. Further investigations prove that most of them are Sigma 3 (60 degrees/< 1 1 0 >) and quasi-Sigma 33c (60 degrees < 1 1 0 >) boundaries with a novel preference of {1 1 0} boundary planes. (C) 2020 Elsevier B.V. All rights reserved.