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Microstructural characterisation of deformation behaviour of nickel base superalloy IN625

Behjati, P ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1179/1743284711Y.0000000056
  3. Abstract:
  4. Simple compression and microscopy techniques were employed to characterise the microstructural origin of the deformation behaviour of nickel base superalloy IN625 during large strain testing. The alloy exhibited a four-stage strain hardening response similar to that previously reported for low stacking fault energy face centred cubic alloys. At strains lower than about -0.06 (stage A), a falling regime of the hardening rate was observed. This stage was followed by a second stage (stage B) of slow increasing hardening rate, which was found to be coincident with the formation of Lomer-Cottrell locks. The second falling regime of strain hardening (stage C) was seen in the strain range of -0.25 to -0.65. The occurrence of this stage was attributed to the increasing ease of dislocation cross-slip with increasing strain and consequently to the decreasing Lomer-Cottrell lock efficiency in hindering dislocation movement. Beyond a strain of 20?65, a final slightly constant hardening regime (stage D) was developed. The initiation of this stage was concurrent with the onset of deformation twinning in the microstructure
  5. Keywords:
  6. Deformation behaviour ; IN625 alloy ; Lomer-Cottrell ; Twinning ; Cross-slip ; Deformation twinning ; Dislocation movement ; Face-centred cubic ; Hardening response ; Large strains ; Lomer-Cottrell locks ; Low stacking fault energies ; Micro-structural ; Microscopy technique ; Microstructural characterisation ; Nickel base superalloy ; Strain ranges ; Deformation ; Strain ; Strain hardening ; Superalloys
  7. Source: Materials Science and Technology ; Volume 27, Issue 12 , 2011 , Pages 1858-1862 ; 02670836 (ISSN)
  8. URL: http://www.maneyonline.com/doi/abs/10.1179/1743284711Y.0000000056?journalCode=mst