Formation of the Fe{sub 23}Zr{sub 6} phase in an Fe-Zr alloy

Journal Article · Tue Jul 15 04:00:00 EDT 1997 · Scripta Materialia

DOI:https://doi.org/10.1016/S1359-6462(97)00074-2· OSTI ID:516851

Abraham, D P; Richardson, Jr, J W; McDeavitt, S M ^[1]

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1. Argonne National Lab., IL (United States). Chemical Technology Div.

Stainless steel-zirconium alloys are being developed at Argonne National Laboratory for the containment and disposal of radioactive metal isotopes isolated from spent nuclear fuel. The nominal compositions that have been selected as waste form alloys are stainless steel-15 wt% zirconium (SS-15Zr) and zirconium-8 wt% stainless steel. To a first approximation, the composition and crystal structure of phases present in these alloys can be inferred from present Fe-Zr phase diagrams. However, many uncertainties exist in the understanding of the Fe-Zr binary, as evidenced by the differing phase diagrams presented by various authors. On the Fe-rich side, the main controversy is over the existence and crystal structure of the Fe{sub 23}Zr{sub 6} (also known as Fe{sub 3}Zr) phase. In this laboratory, Fe-9.8 at% Zr (15 wt% Zr) alloys were prepared and analyzed to resolve the controversy over the Fe{sub 23}Zr{sub 6} phase. Alloys were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and neutron diffraction (ND). The major phases in as-cast alloys were {alpha}-Fe and Fe{sub 2}Zr, whereas the major phases in alloys heat-treated near the eutectic temperature were {alpha}-Fe and Fe{sub 23}Zr{sub 6}. This paper discusses possible mechanisms for the transformation of the Laves intermetallic Fe{sub 2}Zr to the Fe{sub 23}Zr{sub 6} phase during high temperature annealing. An understanding of these mechanisms in the simpler Fe-Zr binary alloy will help in predicting the stability of phases in the SS-15Zr metal waste form alloy.

• Sponsoring Organization: USDOE, Washington, DC (United States)
• OSTI ID: 516851
• Journal Information: Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 2 Vol. 37; ISSN 1359-6462; ISSN SCMAF7
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
36 MATERIALS SCIENCE
INCLUSIONS
INTERMETALLIC COMPOUNDS
IRON BASE ALLOYS
PHASE STUDIES
PHASE TRANSFORMATIONS
RADIOACTIVE WASTE DISPOSAL
STAINLESS STEELS
WASTE FORMS
ZIRCONIUM ALLOYS