THE NATURE OF BAINITE

There are three controversies regarding the formation of bainite. One concerns the mechanism by which lattice atoms leave the fee lattice and form the new bcc lattice. The second one concerns the question of local equilibrium and the role of carbon diffusion. The third one concerns the question whether each little region transforms in two steps or not. These questions are examined in the light of experimental information, including information from very rapid cooling experiments. The information seems to indicate that the lattice atoms move by a diffusive mechanism and there is carbon diffusion under local equilibrium for carbon at the fcc/bcc interface, but not for the lattice atoms.