Characterization of mechanically alloyed powders for high-Cr oxide dispersion strengthened ferritic steel

Noriyuki Y. Iwata, Ryuta Kasada, Akihiko Kimura, Takanari Okuda, Masaki Inoue, Fujio Abe, Shigeharu Ukai, Somei Ohnuki, Toshiharu Fujisawa

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

High-Cr oxide dispersion strengthened (ODS) ferritic steel powders with the nominal composition of Fe-16Cr-4Al-0.1Ti-0.35Y2O3 in wt% were produced by milling of elemental powders and Y2O3 particles in argon atmosphere to investigate changes in the particle properties during mechanical alloying (MA). SEM observation and PSD analysis revealed that the MA powders milled for different times were composed of agglomerated particles having multimodal distributions with substantial size variation ranging from several μm to 350 μm. The mean size of particles rapidly increased at the initial stage of MA, then gradually decreased to 22 μm with increasing milling time up to 48 h, and kept constant thereafter. During milling of the Fe-16Cr-4Al-0.1Ti-0.35Y2O3 powder, MA within 6 h had mainly taken place between Fe and Al to form a bcc-Fe(Al) solid solution. The lattice constant of bcc-Fe steadily increased with a drastic increase in the solute concentrations of Cr, Al, and Ti in Fe. Alloying between Fe and alloying elements is almost fulfilled after milling for 48 h. The MA powder milled in air was much smaller than that milled in gaseous argon under the same conditions. Milling in an air atmosphere is effective to reduce the particle size of the ODS ferritic steel powder, although the pickup of oxygen from environment causes too high excess oxygen content.

Original languageEnglish
Pages (from-to)1914-1919
Number of pages6
JournalIsij International
Volume49
Issue number12
DOIs
Publication statusPublished - 2009 Dec 1
Externally publishedYes

Keywords

  • Mechanical alloying
  • Milling environment
  • Milling time
  • Ods ferritic steel powder

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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