Aluminum depletion induced by co-segregation of carbon and boron in a bcc-iron grain boundary

A. Ahmadian, Daniel Scheiber, Xiang Zhou, Baptiste Gault, C. Liebscher, Lorenz Romaner, Gerhard Dehm

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung

1 Zitat (Scopus)


The local variation of grain boundary atomic structure and chemistry caused by segregation of impurities influences the macroscopic properties of polycrystalline materials. Here, the effect of co-segregation of carbon and boron on the depletion of aluminum at a Σ5 (3 1 0)[0 0 1] tilt grain boundary in a α − Fe-4 at%Al bicrystal is studied by combining atomic resolution scanning transmission electron microscopy, atom probe tomography and density functional theory calculations. The atomic grain boundary structural units mostly resemble kite-type motifs and the structure appears disrupted by atomic scale defects. Atom probe tomography reveals that carbon and boron impurities are co-segregating to the grain boundary reaching levels of >1.5 at%, whereas aluminum is locally depleted by approx. 2 at.%. First-principles calculations indicate that carbon and boron exhibit the strongest segregation tendency and their repulsive interaction with aluminum promotes its depletion from the grain boundary. It is also predicted that substitutional segregation of boron atoms may contribute to local distortions of the kite-type structural units. These results suggest that the co-segregation and interaction of interstitial impurities with substitutional solutes strongly influences grain boundary composition and with this the properties of the interface.

Seiten (von - bis)1-11
FachzeitschriftNature Communications
PublikationsstatusVeröffentlicht - 14 Okt. 2021

Bibliographische Notiz

Funding Information:
We gratefully acknowledge the financial support under the scope of the COMET program within the K2 Center “Integrated Computational Material, Process and Product Engineering (IC-MPPE)” (Project No. 859480). This program is supported by the Austrian Federal Ministries for Transport, Innovation and Technology (BMVIT) and for Digital and Economic Affairs (BMDW), represented by the Austrian research funding association (FFG), and the federal states of Styria, Upper Austria and Tyrol. X.Z. is supported by the Alexander-Humboldt-Stiftung. G.D. gratefully acknowledges support by the ERC Advanced Grant GB-Correlate (Grant Agreement 787446).

Publisher Copyright:
© 2021, The Author(s).

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