entities but are comprised of several small substructural
features.
It is known that the first reaction that influences the
final weld microstructure is inclusion formation, and the
presence of strong deoxidizers such as silicon and
aluminum in high amounts, as in the case of the TRIP
steels under investigation, leads to the formation of
oxide inclusions during welding.[9–13] It is also known
that the reaction between the dissolved alloying elements
in the weld pool with the available oxygen, nitrogen, and
carbon forms nonmetallic inclusions. In TRIP steels,
strong oxidizing elements such as Al and Si are added to
suppress the formation of cementite and thereby to
stabilize the austenite by enriching it with carbon;[1]
however, due to the strong affinity for oxygen, the added
Al and Si readily form oxides during welding, leaving
the weld pool depleted of these elements. This can be
seen from Figure 10, where the energy-dispersive elemental
analysis of the inclusions present in the FZ of the
high-Si steel shows a higher silicon concentration at the
center core as well as at the sides of the inclusion.
Although the bulk manganese content is higher than