Atomic‐Scale Study on Core–Shell Cu Precipitation in Steels: Atom Probe Tomography and Ab Initio Calculations

steel research international, vol. 96

Abstract

In the present work, the atomic interactions among Cu, Al, and Ni elements in body‐centered cubic (BCC) ‐iron matrix, focusing on the formation mechanism of nano‐sized core–shell Cu precipitates, are investigated. In this study, using a combination of atom probe tomography, density‐functional theory (DFT) calculations, and molecular dynamics simulations, insights into the atomic‐scale migration tendencies of these elements in the supersaturated solid solution surrounding Cu precipitate in the martensite phase of a medium‐Mn steel are provided. In the results, it is shown that Ni and Al atoms are not expelled by Cu atoms but are instead attracted to the bcc‐iron matrix, forming a stable co‐segregation in the outer shell. This phase effectively surrounds the nano‐sized Cu precipitate and prevents its rapid growth, contributing to improved mechanical properties. In these findings, a theoretical method is offered for developing Cu‐contaminated circular steels by utilizing DFT calculations to unravel bonding preferences and assess the potential for forming a stable precipitation phase around nano‐sized Cu precipitates.

Authors 7

1. Xiao Huan Shen Aachen Steel Institute

   University of Kassel · RWTH Aachen University

   Affiliation as printed

   Institute of Materials Engineering University of Kassel Mönchebergstr. 3 34125 Kassel Germany

   Steel Institute RWTH Aachen University Intzestr. 1 52072 Aachen Germany

2. Yixu Wang Aachen Institute of Inorganic Chemistry

   RWTH Aachen University

   Affiliation as printed

   Institute of Inorganic Chemistry RWTH Aachen University Landoltweg 1 52056 Aachen Germany

3. Zigan Xu Aachen Steel Institute

   RWTH Aachen University

   Affiliation as printed

   Steel Institute RWTH Aachen University Intzestr. 1 52072 Aachen Germany

4. Bowen Zou

   University of Kassel

   Affiliation as printed

   Institute of Materials Engineering University of Kassel Mönchebergstr. 3 34125 Kassel Germany

5. Enzo Liotti

   University of Oxford

   Affiliation as printed

   Department of Materials University of Oxford Parks Road Oxford OX1 3PH UK

6. Richard Dronskowski Aachen Institute of Inorganic Chemistry

   RWTH Aachen University

   Affiliation as printed

   Institute of Inorganic Chemistry RWTH Aachen University Landoltweg 1 52056 Aachen Germany

7. Wenwen Song corresponding Aachen Steel Institute

   University of Kassel · RWTH Aachen University

   Affiliation as printed

   Institute of Materials Engineering University of Kassel Mönchebergstr. 3 34125 Kassel Germany

   Steel Institute RWTH Aachen University Intzestr. 1 52072 Aachen Germany