Reactive gas atomization processing for Fe-based ODS alloys

TitleReactive gas atomization processing for Fe-based ODS alloys
Publication TypeJournal Article
Year of Publication2012
AuthorsRieken JR, Anderson IE, Kramer MJ, Odette GR, Stergar E, Haney E
Journal TitleJournal of Nuclear Materials
Volume428
Pages65-75
Date Published09
Type of ArticleArticle
ISBN Number0022-3115
Accession NumberWOS:000307153800010
KeywordsFERRITIC ALLOYS, growth, irradiation, metals, recovery, recrystallization, stability, steels
Abstract

Gas atomization reaction synthesis was employed as a simplified method for processing oxide dispersion forming precursor Fe-based powders (e.g., Fe-Cr-Y-Hf). During this process a reactive atomization gas (i.e., Ar-O-2) was used to oxidize the powder surfaces during primary break-up and rapid solidification of the molten alloy. This resulted in envelopment of the powders by an ultra-thin (t < 50 nm) metastable Cr-enriched oxide shell that was used as a vehicle to transport oxygen into the consolidated microstructure. Subsequent elevated temperature heat treatment promoted thermodynamically driven oxygen exchange reactions between trapped films of Cr-enriched oxide and internal (Y, Hf)-enriched intermetallic precipitates, resulting in highly stable nano-metric mixed oxide dispersoids (i.e., Y-Hf-O) that were identified with X-ray diffraction. Transmission electron microscopy and atom probe tomography results also revealed that the size and distribution of the dispersoids were found to depend strongly on the original rapidly solidified microstructure. To exploit this, several oxide dispersion strengthened microstructures were engineered from different powder particle size ranges, illustrating microstructural control as a function of particle solidification rate. Additionally, preliminary thermal-mechanical processing was used to develop a fine scale dislocation substructure for ultimate strengthening of the alloy. Published by Elsevier B.V.

URL<Go to ISI>://WOS:000307153800010
DOI10.1016/j.jnucmat.2011.08.015
Alternate JournalJ. Nucl. Mater.