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

Journal Article


Abstract


  • 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.

Publication Date


  • 2014

Citation


  • Pereloma, E., Alharbi, F. & Gazder, A. A. (2014). The crystallography of carbide-free bainites in thermo-mechanically processed low Si transformation-induced plasticity steels. Journal of Alloys and Compounds, 615 96-110.

Scopus Eid


  • 2-s2.0-84904556667

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/3301

Number Of Pages


  • 14

Start Page


  • 96

End Page


  • 110

Volume


  • 615

Abstract


  • 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.

Publication Date


  • 2014

Citation


  • Pereloma, E., Alharbi, F. & Gazder, A. A. (2014). The crystallography of carbide-free bainites in thermo-mechanically processed low Si transformation-induced plasticity steels. Journal of Alloys and Compounds, 615 96-110.

Scopus Eid


  • 2-s2.0-84904556667

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/3301

Number Of Pages


  • 14

Start Page


  • 96

End Page


  • 110

Volume


  • 615