Fifth European Symposium on Martensitic Transformations and Shape Memory Alloys

J. Phys. IV France 11 (2001) Pr8-217-Pr8-222
DOI: 10.1051/jp4:2001837

Effect of hot-rolling in the austenitic region on the formation of isothermal bainite in a 0.4C-1.5Si-1.4Mn steel

E. Girault¹, S. Godet², P. Jacques^{2, 3}, Ph. Bocher¹, B. Verlinden¹ and J. Van Humbeeck<sup>1

1</sup>  Department of Metallurgy and Materials Engineering, K.U. Leuven, De Croylaan 2, 3001 Leuven, Belgium
²  Université Catholique de Louvain, Département des Sciences des Matériaux et des Procédés, PCIM, place Sainte-Barbe 2, 1348 Louvain-la-Neuve, Belgium
³  McGill University, Department of Metallurgical Engineering, 3610 University Street, Montreal H3A 2B2, Québec, Canada

Abstract
This paper aims to give further insights on the changes that are brought on bainite formation by prior hot-deformation. To this end, a thermomechanical treatment was performed on blocks of a 0.4C-1.5Si-1.4Mn steel. The chemistry of this alloy allowed hot-rolling in the full austenitic range up to large reductions without any significant recrystallisation. The deformed plates were then partially transformed to bainite and the resulting microstructures were subjected to investigation. The laths of bainitic ferrite appeared to be grouped in packets in which they exhibit the same crystallographic orientation. When no prior hot-deformation is applied, the bainite packets originating from the same austenite parent grain were randomly distributed. However, severely deformed austenite grains were found to give rise to typical orientations of the bainitic ferrite laths. These results were interpreted in terms of dislocation arrays interacting with a displacive transformation.

© EDP Sciences 2001