Microstructural characterization of co-based ODS alloys

Lin Zhang, Xuanhui Qu, Xinbo He, Rafi Ud Din, Hengsan Liu, Mingli Qin, Hongmin Zhu

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

Co-based ODS alloys, strengthened by nanosized oxide dispersion and γ′ precipitates, are potential hightemperature structural materials. The characteristics of the mechanically alloyed powder and the microstructural evolution of the Co-based ODS alloys were investigated. The results revealed that mechanical alloying had induced the formation of supersaturated solid solution in immiscible Co-Al-W-based alloys, originating mainly from extensive grain boundary region, high dislocation density, and ample point defect. Chemical compositions of mechanically alloyed Co-Al-W-based ODS alloys easily deviate from the γ/γ′ twophase region, leading to the existence of AlxCo, Co3W, Co7W6, and W phases in addition to the γ and γ′ phases. Nonuniform distribution of alloying elements brings about the differences in morphologies and sizes of γ′ precipitates. Microstructural formation process is impelled by spinodal decomposition mode, and spinodal decomposition behavior has been accelerated in the fine-grained alloy because of the presence of short-circuited diffusion paths for atomic movement.

Original languageEnglish
Pages (from-to)2487-2494
Number of pages8
JournalJournal of Materials Engineering and Performance
Volume21
Issue number11
DOIs
Publication statusPublished - 2012 Nov 1
Externally publishedYes

Keywords

  • Cobalt-based alloy
  • Mechanical alloying
  • Microstructure
  • Oxide dispersion strengthening
  • Spinodal decomposition

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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