Temperature dependence of carbon supersaturation of ferrite in bainitic steels

The carbon supersaturation of bainitic ferrite was investigated by means of atom probe tomography in three steels with different carbon and silicon contents, to elucidate the effect of transformation temperature and the reaction velocity on the mechanisms controlling bainite formation with and without the interference of cementite precipitation. Results indicated no difference in the growth mechanism over the temperature range investigated. These results provide new evidence that the bainite transformation is essentially martensitic in nature.