Studies on alloying process of a ferritic/martensitic oxide dispersion strengthened (ODS) steel prepared by mechanical alloying of elemental powders

Abstract

Ferritic/martensitic oxide dispersion strengthened steel with a nominal composition of Fe–9Cr–2W–0.2Ti–0.12C–0.35Y₂O₃ was produced by mechanical alloying in a high energy horizontal Simoloyer attritor. Powder samples were collected at intervals of 0.5, 1, 2, 3, 5, 7 and 10 h and analysed by X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy and differential thermal analysis. The alloying elements (Cr and W) got dissolved in the matrix in 7 h milled powder. Crystallite size decreased rapidly with milling time up to 5 h milling and reached a stable size of ∼12 nm after 7 h, whereas strain and lattice parameter were found to increase with milling time. The particle size increased up to 2 h milling and then decreased with milling time. A fine and uniform particle size of ∼25 nm was obtained after 7 h milling. The alloying process and distribution of alloying elements/Y₂O₃ is studied in the present work.

Keywords:

• ODS Steels
• High temperature materials
• Fast breeder nuclear reactor
• Powder metallurgy
• Mechanical alloying
• Simoloyer attritor

Acknowledgements

Authors are grateful to Board of Research in Nuclear Sciences (BRNS), Mumbai for funding this work.

ORCID

S. K. Rajulapati http://orcid.org/0000-0002-6573-6436