Elemental redistribution in a nanocrystalline Ni-Fe alloy induced by high-pressure torsion

An electrochemically deposited nanocrystalline supersaturated face-centred-cubic Ni-21. at.% Fe alloy with an initial average grain size of ∼21. nm was processed using high-pressure torsion (HPT) that resulted in grain growth via grain rotation and coalescence to an average grain size of ∼53. nm. Atom probe tomography investigations revealed that the supersaturated Ni-Fe solid solution was stable under HPT and that C and S atoms, which are the major impurities in the material and segregated to the grain boundaries (GBs) of the as-deposited material, migrated from disappearing GBs to the remaining GBs during HPT. We propose that the elemental redistribution was facilitated by GB diffusion and the motion of a large volume of HPT-induced defects at the GB regions during the grain growth process. This elemental redistribution process is different from other HPT-induced elemental redistribution processes reported in the literature. © 2011 Elsevier B.V.