Chemical and structural evolution of nano-oxides from mechanical alloying to consolidated ferritic oxide dispersion strengthened steel. (July 2022)

• Record Type: Journal Article
• Authors: Spartacus, Gabriel; Malaplate, Joël; De Geuser, Frédéric; Mouton, Isabelle; Sornin, Denis; Perez, Michel; Guillou, Raphaëlle; Arnal, Benoit; Rouesne, Elodie; Deschamps, Alexis
• Is Part Of: Acta materialia. Volume 233(2022)
• Publication Date: 2022-07
• Subjects: ODS Oxides Dispersion Strengthened -- MA Mechanical Alloying -- SFR Sodium-cooled Fast Reactors -- GBs Grain Boundaries -- APT Atom Probe Tomography -- SAS Small Angle Scattering -- SAXS Small Angle X-Ray Scattering -- SANS Small Angle Neutron Scattering -- HE Hot Extrusion -- HIP Hot Isostatic Pressing -- TEM Transmission Electron Microscopy -- PCF Pair Correlation Function -- RDF Radial Distribution Function; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2022.117992
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: Ferritic Oxides Dispersion Strengthened (ODS) steels are of great interest for nuclear fission and fusion power plants. The nano-oxides embedded into the matrix provide the main contribution to the ODS steel strength. Understanding of the precipitation mechanism of ODS steels is thus critical for optimizing the fabrication process, involving Mechanical Alloying (MA) of Fe-14Cr, Y2 O3 and TiH2 powders. In this study, results from small-angle X-ray and neutron scattering, atom probe tomography and electron microscopy have been combined to investigate the nano-oxides evolution throughout the whole consolidation thermal treatment until 1100 °C. After MA clusters are observed, composed of Y, O and Ti. During heating these clusters grow and new ones nucleate, together with a sequential enrichment in Ti (from as-MA to 700 °C) and Y (between 900 and 1100 °C). A small quantity of Al is also found in the nano-oxides between 700 and 1100 °C. At 1100 °C the nano-oxides are found to be mainly Y2 Ti2 O7 and subsequently progressively transform to Y2 TiO5 during isothermal holding. Nano-oxides display however an unchanged extremely low coarsening rate, demonstrating the outstanding stability of both Y2 Ti2 O7 and Y2 TiO5 at 1100 °C. Graphical abstract: Image, graphical abstract