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

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-richmore » precipitate was observed after creep. • The predicted size of precipitates by MatCalc agreed well with measured size.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [1] ;  [2] ;  [1] ;  [2] ;  [1] ;  [1]
  1. High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of)
  2. (Korea, Republic of)
  3. Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22285077
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 83; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AUSTENITIC STEELS; CARBONITRIDES; CHROMIUM NITRIDES; CREEP; DENSITY; PARTICLES; PRECIPITATION; THERMODYNAMICS