First-principles insights into micro-alloying roles of Zr in Cu-Cr-Zr alloys

Interface has been often neglected in exploring micro-alloying mechanisms in polycrystalline CueCreZr alloys. In this study, interface structure modeling and first-principles calculations were carried out to explore the segregation behaviors of micro-alloying element Zr at nano-Cr particle interfaces and a series of low-Sigma (Sigma <= 11) Cu grain boundaries (GBs) in CueCreZr alloys. The segregation effects on interface adhesion strength were also evaluated. Our results suggested that Zr can substitute the top-most Cu atoms at most nano-Cr particle interfaces (those with the NishiyamaeWassermann orientation relation) with the maximal coverage of 1/3 ML. The segregation to other nano-Cr interfaces with the KurdjumoveSachs orientation relation is, however, energetically forbidden. At almost all the low-Sigma GBs (except the Sigma 3 (111) only), Zr segregation can be consistently favored up to a full coverage (1 ML), which can improve the GB binding by similar to 30%. Based on these results, the multi-fold benefits of Zr micro-alloying were discussed. (c) 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Interface structure modeling and first-principles calculations were performed to investigate the segregation behaviors of Zr micro-alloying element at nano-Cr particle interfaces and low-Sigma Cu grain boundaries in CueCreZr alloys. The results showed that Zr can substitute Cu atoms at nano-Cr interfaces with the Nishiyama-Wassermann orientation relation, but not at interfaces with the Kurdjumove-Sachs orientation relation. Zr segregation at low-Sigma grain boundaries greatly improved the binding strength.