Direct observation of solute-dislocation interaction on screw dislocation in a neutron irradiated modified 316 stainless steel

A three-dimensional atom probe (3DAP) technique was used to observe the three-dimensional solute distribution around screw dislocations in neutron-irradiated modified 316 austenitic stainless steel. Si, Ni, and P were observed to get enriched around the cores of screw dislocations, while Fe, Cr, Mn, and Mo were depleted in the same areas. Si was segregated to a narrow region in the core for which, it was concluded that Si was trapped in the initial stage of segregation. Other enriched elements segregated to some edge features such as kinks and/or jogs formed as a result of Si trapping. The results suggest that solute-dislocation interaction of screw dislocations was similar to radiation-induced segregation, which is affected by the volume size factor of solute atoms.