Re segregation at interfacial dislocation network in a nickel-based superalloy

Qingqing Ding, Suzhi Li, Long-qing Chen, Xiaodong Han, Ze Zhang, Qian Yu, Jixue Li

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

The distribution of Rhenium (Re) in a Ni-based single-crystal superalloy is studied by sub-angstrom resolution transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). It is found that Re atoms segregate at the tensile stress regions near the interfacial dislocation cores, forming the “Cottrell atmosphere” and the segregation process is facilitated by dislocation pipe diffusion. In situ TEM and scanning electron microscopy (SEM) straining studies reveal that the Re-decorated dislocation networks along the phase boundaries act as mechanical walls that effectively block dislocation motion and crack propagation. Furthermore, the degree of Re segregation can be regulated by thermal treatment. Theoretical analysis demonstrates that this remarkable alloying effect originated mainly from the interactions between the local composition strain of Re and the dislocation strains, leading to significantly stabilized interfacial dislocation networks. These results provide a new perspective on understanding the origin of the Re effect on mechanical properties in Ni-based superalloys and will be beneficial to both improving creep properties of Ni-based superalloys and designing high-performance Re-free superalloys.

Original languageEnglish (US)
Pages (from-to)137-146
Number of pages10
JournalActa Materialia
Volume154
DOIs
StatePublished - Aug 1 2018

Fingerprint

Rhenium
Nickel
Superalloys
Transmission electron microscopy
Phase boundaries
Alloying
Tensile stress
Energy dispersive spectroscopy
Crack propagation
Creep
Heat treatment
Pipe
Single crystals
Atoms
Mechanical properties
Scanning electron microscopy
Chemical analysis

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

Cite this

Ding, Qingqing ; Li, Suzhi ; Chen, Long-qing ; Han, Xiaodong ; Zhang, Ze ; Yu, Qian ; Li, Jixue. / Re segregation at interfacial dislocation network in a nickel-based superalloy. In: Acta Materialia. 2018 ; Vol. 154. pp. 137-146.
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Re segregation at interfacial dislocation network in a nickel-based superalloy. / Ding, Qingqing; Li, Suzhi; Chen, Long-qing; Han, Xiaodong; Zhang, Ze; Yu, Qian; Li, Jixue.

In: Acta Materialia, Vol. 154, 01.08.2018, p. 137-146.

Research output: Contribution to journalArticle

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AU - Ding, Qingqing

AU - Li, Suzhi

AU - Chen, Long-qing

AU - Han, Xiaodong

AU - Zhang, Ze

AU - Yu, Qian

AU - Li, Jixue

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AB - The distribution of Rhenium (Re) in a Ni-based single-crystal superalloy is studied by sub-angstrom resolution transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). It is found that Re atoms segregate at the tensile stress regions near the interfacial dislocation cores, forming the “Cottrell atmosphere” and the segregation process is facilitated by dislocation pipe diffusion. In situ TEM and scanning electron microscopy (SEM) straining studies reveal that the Re-decorated dislocation networks along the phase boundaries act as mechanical walls that effectively block dislocation motion and crack propagation. Furthermore, the degree of Re segregation can be regulated by thermal treatment. Theoretical analysis demonstrates that this remarkable alloying effect originated mainly from the interactions between the local composition strain of Re and the dislocation strains, leading to significantly stabilized interfacial dislocation networks. These results provide a new perspective on understanding the origin of the Re effect on mechanical properties in Ni-based superalloys and will be beneficial to both improving creep properties of Ni-based superalloys and designing high-performance Re-free superalloys.

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