Modelling grain boundary sliding during creep of austenitic stainless steels
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Two models are presented for grain boundary sliding (GBS) displacement during creep. GBS is considered as crucial for the formation of creep cavities. In the first model, the shear sliding model, GBS is accommodated by grains freely sliding along the boundaries in a power-law creeping material. The GBS rate is proportional to the grain size. In the second model, the shear crack model, the sliding boundaries are represented by shear cracks. The GBS rate is controlled by particles in the boundaries. In both models, the GBS displacement rate is proportional to the creep strain rate. Both models are consistent with existing experimental observations for GBS during creep of austenitic stainless steels. For cavity nucleation at particles, Harris’ model (1965) for the relationship between GBS and a critical particle size has been analysed and found to be in agreement with observations.
KeywordsCreep Rate Austenitic Stainless Steel Creep Strain Shear Crack Grain Boundary Slide
Financial support by the European Union (directorate-general for energy), within the project MACPLUS (ENER/FP7EN/249809/MACPLUS) in the framework of the Clean Coal Technologies is gratefully acknowledged. The authors would like to thank the China Scholarship Council (CSC) for funding a stipend (File No. 201207090009) for Junjing He.
Compliance with ethical standards
Conflict of Interest
The authors declare that they have no conflict of interest.
- 16.Harris JE (1965) Nucleation of creep cavities in magnesium. Trans Metall Soc AIME 233:1509Google Scholar
- 18.He J, Sandström R (2015) Formation of creep cavities in austenitic stainless steels (in press)Google Scholar
- 19.McLean D, Farmer MH (1957) The relation during creep between grain-boundary sliding, sub-crystal size, and extension. J Inst Met 85(8):41–50Google Scholar
- 22.Kishimoto S, Shinya N, Tanaka H (1987) Grain boundary sliding and surface cracking during creep of 321 stainless steel. Materials 37(414):289–294Google Scholar
- 28.Arzate OR, Martinez L (1988) Creep cavitation in type 321 stainless steel. Mater Sci Eng A 101:1–6Google Scholar
- 30.Farooq M (2013) Strengthening and degradation mechanisms in austenitic stainless steels at elevated temperature. KTH Royal Institute of Technology, StockholmGoogle Scholar
- 33.Arai M, Ogata T, Nitta A (1996) Continuous observation of cavity growth and coalescence by creep-fatigue tests in SEM. Jpn Soc Mech Eng 39(3):382–388Google Scholar
- 34.NIMS creep data sheet for austenitic stainless steels. http://smds.nims.go.jp/creep/index_en.html
- 36.AHV (1991) Properties and selection: nonferrous alloys and special-purpose materials, vol 2. ASM International, Materials ParkGoogle Scholar
- 38.Vujic S, Sandström R, Sommitsch C (2015) Precipitation evolution and creep strength modelling of 25Cr20NiNbN austenitic steel. Mater High Temp. doi: 10.1179/1878641315Y.0000000007