The crystallography of carbide-free bainites in thermo-mechanically processed low Si transformation-induced plasticity steels

作者：Pereloma Elena V; Al Harbi Fayez; Gazder Azdiar A^*

来源：Journal of Alloys and Compounds, 2014, 615: 96-110.

DOI：10.1016/j.jallcom.2014.05.123

• Transformation induced plasticity (TRIP)
• Steel
• Electron back-scattering diffraction (EBSD)
• Bainite transformation
• Kurdjumov-Sachs orientation relationship

Carbide-free bainites are important microstructural constituents in bainitic, nanobainitic and transformation-induced plasticity (TRIP) steels. A comparison of the crystallography of ferrite in granular bainite and bainitic ferrite lath morphologies, both of which were simultaneously present in a base and a Nb-Ti containing TRIP steel, has been carried out using electron back-scattering diffraction. Ferrite in granular bainite was characterised by the realisation of nearly all 24 variants of the Kurdjumov-Sachs orientation relationship; which in turn was associated with the self-accommodation of the transformation strain. On the other hand, bainitic ferrite comprised a mostly parallel lath structure between thick interlayers of retained austenite and exhibited variant selection such that one or more crystallographic packets are not realised and sometimes only 1-2 variants formed in a crystallographic packet. The variant selection in bainitic ferrite laths was associated with: (i) the plastic accommodation of transformation strain by retained austenite and, (ii) the limited available volume for its formation.

• 出版日期2014-12-5