Austenite-martensite/bainite orientation relationship: characterisation parameters and their application
V. Yardley, E. Payton.
Materials Science and Technology, Maney Publishing, Leeds, 30, 1125-1130, (2014)
Transformations from austenite to martensite or bainite in ferrous alloys have great technological importance, but some aspects remain elusive. The orientation relationship (OR), morphology and habit plane can vary considerably from one system to another. Much published work considers these OR in terms of their variation from named relationships such as Kurdjumov-Sachs and Nishiyama-Wassermann. We discuss here, instead, the use of a set of angular parameters based on the classic work of Kurdjumov and Sachs in the 1930s, that provide a unified and elegant description facilitating extraction and detailed statistical treatment of OR from large electron backscatter diffraction datasets, as well as straightforward comparison with named OR and with the predictions from the phenomenological theory. Spatially correlated mappings of OR parameters obtained using this approach suggest that the observed variations in OR are related to the martensitic morphology rather than being an experimental artefact.
Keyword(s): Martensitic transformations; Bainitic transformations; Orientation relationship; Electron backscatter diffraction; Microstructure