An investigation of the mechanism of bainite transformation in experimental 0.2c-1v-2mn steel

Abstract

The paper presents an investigation of the mechanism of bainite transformation in 0.2C-1V-2Mn steel using high speed dilatometry and TEM backed by thermodynamic analysis. Obtained results confirm the incomplete reaction phenomenon with the cessation of the bainite transformation well before paraequilibrium is achieved. These experimental data indicate that bainitic ferrite forms by a displacive transformation mechanism, but soon afterwards, excess of carbon is partitioned into the residual austenite. The results are discussed in terms of the mechanism of bainite transformation.

Influence of Intermediate Annealing Treatment on the Kinetics of Bainitic Transformation in X37CrMoV5-1 Steel

“…Blocking the growth of subunits causes new nucleations, which allow the transformation to continue [68]. Immediately after the formation of subunits, due to the lower solubility of carbon in ferrite than austenite, excess carbon is ejected from the subunits [69]. Bainite formation is continued by the autocatalytic nucleation of bainitic ferrite on the newly formed subunits.…”

“…Bainite formation is continued by the autocatalytic nucleation of bainitic ferrite on the newly formed subunits. New subunits usually nucleate more frequently near the sharp edges of other bainitic ferrite plates than on their flat surfaces [68,69]. The blocking of the growth of subsequent subunits is due to the stress field around the plate, a collision with other plates, or with PAGBs [70].…”