Effect of Mo:W ratio on segregation behavior and creep strength of nickel-based single crystal superalloys

Longfei Zhang, Zaiwang Huang, Liang Jiang, Junhua Luan, Zengbao Jiao, Chain Tsuan Liu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

6 Citations (Scopus)

Abstract

In past decades, molybdenum (Mo) has demonstrated the potential to replace tungsten (W) in designing lighter nickel-based single crystal superalloys with enhanced creep resistance. In this research, three groups of nickel-based single crystal superalloys are designed and prepared by tuning the Mo:W ratio. The experimental observations show that the primary and secondary dendrite arm spacings are both independent on Mo:W ratio, but the γ/γ′ eutectic volume fraction decreases as Mo:W ratio increases. The electron probe microanalysis reveals that Re, W and Co segregate to dendrite core regions, while Al, Ti, Cr, Mo and Ta to interdendritic regions. The microsegregation of Ta, W and Re are gradually relieved with increasing Mo:W ratio. Atom probe tomography results further indicate that Cr and Mo are depleted in γ/γ′ eutectics, leading to the enrichment of Cr and Mo at interdendritic regions away from γ/γ′ eutectics. Creep rupture results show that the rupture life at 1040 °C/145 MPa is improved as Mo:W ratio increases.

Original languageEnglish
Pages (from-to)481-489
Number of pages9
JournalMaterials Science and Engineering A
Volume744
DOIs
Publication statusPublished - 28 Jan 2019

Keywords

  • Alloy design
  • Creep rupture
  • Microsegregation
  • Mo:W ratio
  • Nickel-based single crystal superalloys
  • γ/γ′ eutectic

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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