Pt accelerated coarsening of A15 precipitates in Cr-Si alloys

Anke S. Ulrich*, Alexander J. Knowles, Valentina Cantatore, Ayan Bhowmik, Michael T. Wharmby, Christine Geers, Itai Panas, Mathias C. Galetz

*Corresponding author for this work

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Abstract

The effect of alloying Cr-rich Cr-Si alloys with Pt was investigated by a combination of complementary experimental methods and atomic scale modelling. The investigated Cr-Si and Cr-Si-Pt (Cr ⩾86 at.%) alloys developed a two-phase microstructure consisting of Cr solid solution (Crss) matrix and strengthened by A15 precipitates during annealing at 1200°C. It was found that additions of 2 at.% Pt increase the coarsening rate by almost five times considering annealing times up to 522 h. Pt was found to change the precipitate matrix orientation relationship, despite its low influence on the Crss matrix/A15 precipitate misfit. Through this experimental and modelling approach new insight has been gained into mechanisms of enhanced coarsening by Pt addition. The increased coarsening is principally attributed to a change in interface composition and structure resulting in different thermodynamic stabilities: Pt-containing A15 phase was found to have a broader compositional range if both elements, Pt and Si, are present compared to only Si. Additionally, the Crss phase was found to have a higher solubility of Pt and Si over just Si. Both factors additionally facilitated Ostwald ripening.

Original languageEnglish
Article number110655
Number of pages17
JournalMaterials and Design
Volume218
Early online date6 May 2022
DOIs
Publication statusPublished - Jun 2022

Bibliographical note

Funding Information:
This paper is developed as part of the COMPASsCO2 project, which has received funding from the European Union’s Horizon 2020 Research and Innovation Action (RIA) under grant agreement No. 958418. Additionally, it is funded by the Swedish Energy Authority and the Swedish Foundation for Strategic Research project SAFETY (SSF: EM16-0031). This project has received funding from the Chalmers Area of Advance-ENERGY under the funding ID "Light-weight high temperature materials beyond nickel-base alloys". The computations were performed on resources at Chalmers Centre for Computational Science and Engineering (C3SE) provided by the Swedish National Infrastructure for Computing (SNIC). A. Knowles thanks the EUROfusion Research Grant (AWP17-ERG-CCFE/Knowles) and the Royal Academy of Engineering Research Fellowship (RF\201819\18\158) for the financial support. A. S. Ulrich and A. J. Knowles additionally thank the European Feration of Corrosion (EFC) EUROCORR Young Scientist Grant 2019 (EFC-YSG-2019-4) for supporting collaborative TEM investigations.

The authors thank Dr. G. Schmidt from DECHEMA-Forschungsinstitut for EPMA measurements. The authors would also like to express their gratitude to the Plansee Group for providing the chromium raw material used in this work. We acknowledge DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities. Parts of this research were carried out at PETRA III using beamline P02.1.

Publisher Copyright:
© 2022 The Authors

Keywords

  • Coarsening mechanism
  • Density functional theory
  • High temperature materials
  • Orientation relationship
  • Transition-metal silicides

ASJC Scopus subject areas

  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering

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