J. Mater. Sci. Technol. ›› 2023, Vol. 134: 223-233.DOI: 10.1016/j.jmst.2022.06.028

• Research Article • Previous Articles     Next Articles

Stabilizing nanograined Fe-Cr alloy by Si-assisted grain boundary segregation

X.F. Xua,b, X.Y. Lia,*(), B. Zhanga   

  1. aShenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
    bSchool of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
  • Received:2022-04-24 Revised:2022-06-13 Accepted:2022-06-16 Published:2023-01-20 Online:2023-01-10
  • Contact: X.Y. Li
  • About author:* E-mail address: xyli@imr.ac.cn (X.Y. Li).

Abstract:

Intentional solute segregation at grain boundary (GB) can effectively stabilize the nanograined alloys by reducing the excess energy and mobility of GB, but it usually works for binary alloys with sufficient GB segregation tendency. Here, we found that the segregation of Cr can be enhanced in a nanostructured Fe-8Cr alloy with insufficient GB segregation tendency through the interaction of another solute Si (1.0 wt.%). After surface mechanical grinding treatment and subsequent annealing, the nanograined Fe-8Cr-1Si is more thermally stable than the nanograined Fe-8Cr, which is mainly attributed to the Si-enhanced Cr segregation as observed by Super-X energy-dispersive X-ray spectroscopy (EDS) mapping system. With the grain refinement to nanoscale, the thermal stability is further improved due to the increase of Cr content at GBs and the precipitates formed at appropriate high temperatures. The present finding provides guidance for the development of advanced nanostructured ternary alloys.

Key words: Segregation, Grain boundary, Fe-Cr-Si alloy, Nanocrystalline, Thermal stability