Effect of Nb and Cu on the high temperature creep properties of a high Mn–N austenitic stainless steel

Journal Article · Sun Sep 15 04:00:00 EDT 2013 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2013.05.015· OSTI ID:22285077

Lee, Kyu-Ho ^[1]; Suh, Jin-Yoo ^[1]; Huh, Joo-Youl ^[2]; Park, Dae-Bum ^[1]; Hong, Sung-Min ^[1]; Shim, Jae-Hyeok ^[1]; Jung, Woo-Sang ^[1]

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1. High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of)
2. Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

The effect of Nb and Cu addition on the creep properties of a high Mn–N austenitic stainless steel was investigated at 600 and 650 °C. In the original high Mn–N steel, which was initially precipitate-free, the precipitation of M{sub 23}C{sub 6} (M = Cr, Fe) and Cr{sub 2}N took place mostly on grain boudaries during creep deformation. On the other hand, the minor addition of Nb resulted in high number density of Z-phases (CrNbN) and MX (M = Nb; X = C, N) carbonitrides inside grains by combining with a high content of N, while suppressing the formation of Cr{sub 2}N. The addition of Cu gave rise to the independent precipitation of nanometer-sized metallic Cu particles. The combination of the different precipitate-forming mechanisms associated with Z-phase, MX and Cu-rich precipitates turned out to improve the creep-resistance significantly. The thermodynamics and kinetics of the precipitation were discussed using thermo-kinetic simulations. - Highlights: • The creep rupture life was improved by Nb and Cu addition. • The creep resistance of the steel A2 in this study was comparable to that of TP347HFG. • The size of Z-phase and MX carbonitride did not change significantly after creep test. • The nanometer sized Cu-rich precipitate was observed after creep. • The predicted size of precipitates by MatCalc agreed well with measured size.

• OSTI ID: 22285077
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Vol. 83; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AUSTENITIC STEELS
CARBONITRIDES
CHROMIUM NITRIDES
CREEP
DENSITY
PARTICLES
PRECIPITATION
THERMODYNAMICS