The transmission electron microscopy (TEM) image series shows interrelations between nitrides and carbonitrides in boron microalloyed steel. The different phases are distinguished by different gray scales.
-) On the left upper side, the mutual growth of AlN and BN is shown.
-) On the right upper side, TiN is contributing to the carbonitride phase interrelations due to Ti alloying. It is obvious that AlN can form individual particles.
-) On the lower image row, it appears that the three different precipitates can grow on each other.
We found new evidence by using 3D-APT (atom probe tomography) for enrichment of Boron at interfaces, including the interface between naon-sized Carbide particles and the steel matrix of boron-microalloyed steel. This finding raises the important and fundamental question of competition between thermodynamic equilibrium dissolution of an element in the crystallographic lattice of, e.g., a carbide particle, and the kinetic attachment of such segregating species. The two scenarios lead to a different prediction of materials response during thermal processing.
