Microstructure Evolution of Gas Atomized Iron Based ODS Alloys
In a simplified process to produce precursor powders for oxide dispersion-strength- ened (ODS) alloys, gas-atomization reaction synthesis (GARS) was used to induce a surface oxide layer on molten droplets of three differing erritic stainless steel alloys during break-up and rapid solidification. The chemistry of the surface oxide was identified using auger electron spectroscopy (AES) and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). The precursor iron-base powders were consolidated at 850 C and 1,300 C using hot isostatic pressing (HIPing). Consolidation at the lower temperature resulted in a fully dense microstructure, while preventing substantial prior particle-boundary-oxide dissociation. Microstructural analysis of the alloys consolidated at the higher temperature confirmed a significant reduction in prior-particle-boundary-oxide volume fraction, in comparison with the lower-temperature-consolidated sample. This provided evidence that a high-temperature internal oxygen-exchange reaction occurred between the metastable prior particle-boundary-oxide phase (chromium oxide) and the yttrium contained within each prior particle. This internal oxygen-exchange reaction is shown to result in the formation of yttrium-enriched oxide dispersoids throughout the alloy microstructure. The evolving microstructure was characterized using transmission electron microscopy (TEM) and high-energy X-ray diffraction (HE-XRD).
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1009067
- Resource Relation:
- Conference: Advances in Powder Metallurgy & Particulate Materials—2009;June 28 - July 1, 2009;Las Vegas, NV
- Country of Publication:
- United States
- Language:
- ENGLISH
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Related Subjects
ALLOYS
AUGER ELECTRON SPECTROSCOPY
CHEMISTRY
CHROMIUM
DISSOCIATION
HOT PRESSING
IRON
MICROSTRUCTURE
OXIDES
PARTICULATES
POWDER METALLURGY
PRECURSOR
SCANNING ELECTRON MICROSCOPY
SOLIDIFICATION
SPECTROSCOPY
STAINLESS STEELS
SYNTHESIS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
YTTRIUM