Report on the FY20 Characterization of Age Hardened Alloy 709 Materials

Technical Report · Sat Aug 01 04:00:00 EDT 2020

DOI:https://doi.org/10.2172/1656885· OSTI ID:1656885

Zhang, X. ^[1]; Sham, T. -L. ^[2]

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1. Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Science and Engineering Division
2. Argonne National Lab. (ANL), Argonne, IL (United States). Applied Materials Division

This report provides the results on microstructural characterization of the first commercial heat of Alloy 709 plate material undergone additional age hardening treatment. In FY19, through thermodynamic-kinetic modeling and microstructural characterization, it is determined that the 775°C/10 h age-hardening treatment can promote desired precipitation on dislocations and has the potential to further improve the mechanical performance of the material. In FY20, the treatment protocol was applied to the ESR-1150°C condition, and the microstructure was then compared with the ESR-1100°C condition. It was found that the 1150°C solution annealing (SA) dramatically reduced the dislocation density compared to the 1100°C SA, resulting a smaller number density of Nb-rich fine precipitates which grow on dislocations during the age hardening treatment. Other features are very similar between the two. The effect of age hardening on creep performance is discussed. In addition, TEM characterization of a creep-ruptured sample (600°C/330 MPa) was performed. Specimens from the grip region and the gauge region was studied. The grip region specimen was effectively aged at 600°C for extended period, while the gauge region specimen was mechanically deformed at 600°C. The microstructures are very different, implying the importance of a dynamical effect on precipitation.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1656885
• Report Number(s): ANL-ART--192; 161914
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
36 MATERIALS SCIENCE