Impact of the segregation energy spectrum on the enthalpy and entropy of segregation

Substantial disagreement exists for segregation energies between experimentally measured and first prin-ciples calculated values. To resolve this standing issue, we computed segregation of five different ele-ments to the same grain boundaries as studied in an previous experimental investigation. We show that the multi-site nature of segregation leads to a strong artificial temperature dependence in the single site effective segregation energy. Taking this into account leads to a highly improved agreement between ex-periment and theory and clarifies the nature of experimentally determined segregation enthalpies and entropies. (c) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

There is substantial disagreement between experimentally measured and first principles calculated values for segregation energies. By computing segregation of five different elements to the same grain boundaries as studied in previous experiments, it was found that the multi-site nature of segregation leads to artificial temperature dependence in the single site effective segregation energy. Taking this into account significantly improves the agreement between experiment and theory, and clarifies the nature of experimentally determined segregation enthalpies and entropies.