Advanced TEM characterization of oxide nanoparticles in ODS Fe–12Cr–5Al alloys

Journal Article · Fri Jan 01 00:00:00 EST 2016 · Journal of Materials Science

DOI:https://doi.org/10.1007/s10853-016-0111-5· OSTI ID:1325439

Unocic, Kinga A. ^[1]; Pint, Bruce A. ^[1]; Hoelzer, David T. ^[1]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

For oxide nanoparticles present in three oxide-dispersion-strengthened (ODS) Fe–12Cr–5Al alloys containing additions of (1) Y₂O₃ (125Y), (2) Y₂O₃ + ZrO₂ (125YZ), and (3) Y₂O₃ + HfO₂ (125YH), were investigated using transmission and scanning transmission electron microscopy. Furthermore, in all three alloys nano-sized (<3.5 nm) oxide particles distributed uniformly throughout the microstructure were characterized using advanced electron microscopy techniques. In the 125Y alloy, mainly Al₂O₃ and yttrium–aluminum garnet (YAG) phases (Y₃Al₅O₁₂) were present, while in the 125YZ alloy, additional Zr(C,N) precipitates were identified. The 125YH alloy had the most complex precipitation sequence whereby in addition to the YAG and Al₂O₃ phases, Hf(C,N), Y₂Hf₂O₇, and HfO₂ precipitates were also found. The presence of HfO₂ was mainly due to the incomplete incorporation of HfO₂ powder during mechanical alloying of the 125YH alloy. The alloy having the highest total number density of the oxides, the smallest grain size, and the highest Vickers hardness was the 125YZ alloy indicating, that Y₂O₃ + ZrO₂ additions had the strongest effect on grain size and tensile properties. Finally, high-temperature mechanical testing will be addressed in the near future, while irradiation studies are underway to investigate the irradiation resistance of these new ODS FeCrAl alloys.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
• Sponsoring Organization: USDOE Office of Science (SC), Fusion Energy Sciences (FES)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1325439
• Journal Information: Journal of Materials Science, Vol. 51, Issue 20; ISSN 0022-2461
• Publisher: Springer
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE