Open Questions in Nanosegregation

Abstract

Despite nanosegregation of solutes at grain boundaries has been intensively studied in the past decades and numerous theoretical data as well as experimental values on characteristic energies and/or enthalpies and entropies exist some questions remain still unanswered. In this paper some of these questions – Which energetic quantities obtained in different ways, experimentally and theoretically, can be mutually compared? What is the segregation site of a solute in the grain boundary core? – are discussed in more detail. It will be shown that the entropy of grain boundary segregation plays an important and indisputable role in responding some issues and that understanding of its role will help us to elucidate fundamentals of the grain boundary segregation.