Acta Metallurgica Sinica (English Letters) ›› 2024, Vol. 37 ›› Issue (2): 364-372.DOI: 10.1007/s40195-023-01621-9

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Developing Core-Shell Nano-Structures in FeCrAl-ODS Ferritic Alloys with the Co-Addition of Ni and Zr

Wenquan Ding1, Jieli Ma1, Yong Jiang1,2(), Yiren Wang1, Huiqun Liu1   

  1. 1Key Laboratory for Nonferrous Materials of Ministry of Education, School of Materials Science and Engineering, Central South University, Changsha, 410083, China
    2National Key Laboratory for Powder Metallurgy, Central South University, Changsha, 410083, China
  • Received:2023-04-08 Revised:2023-04-28 Accepted:2023-05-15 Online:2024-02-10 Published:2024-02-27
  • Contact: Yong Jiang, yjiang@csu.edu.cn

Abstract:

A new Ni + Zr co-alloyed FeCrAl-ODS (oxide-dispersion-strengthened) ferritic alloy was fabricated by ball-milling and hot-isostatic-pressing. Using electron microscopy and atom probe tomography, the dispersive formation of high density core-shelled nano-particles of various sizes was confirmed with a common B2-NiAl shell. Among which, median-sized nano-particles (20-50 nm) typically have an Y4Al2O9 nano-core of <  ~ 20 nm, ultra-fine nano-particles (< ~ 20) nm have an Y4Zr3O12 nano-core of <  ~ 10 nm, and larger-sized nano-particles (50-100 nm) incorporate an ultra-fine Y4Al2O9 nano-core and a few ultra-fine Y4Zr3O12 nano-oxides. All these nano-phases were highly coherent with the ferritic matrix. No large Y-Al-O nano-oxides were formed. The total number density of ultra-fine nano-particles was estimated as ~ 2 × 1023 m−3 with a mean size of 6.3 nm only, and accordingly, the new alloy achieved an excellent combination of strength and ductility at high temperatures.

Key words: FeCrAl, Oxide-dispersion-strengthened (ODS) alloy, Mechanical alloying, Nano-oxides, Core-shell