Competition between work-hardening effect and dynamic-softening behavior for processing as-cast GH4720Li superalloys with original dendrite microstructure during moderate-speed hot compression

Y. Q. Ning, T. Wang, Mingwang Fu, M. Z. Li, L. Wang, C. D. Zhao

Research output: Journal article publicationJournal articleAcademic researchpeer-review

34 Citations (Scopus)

Abstract

Competition between work-hardening effect and dynamic-softening behavior of as-cast GH4720Li superalloys with original dendrite microstructure during moderate-speed deformation was quantitatively investigated in this present paper. Flow behavior for processing the studied alloys with dendrite microstructure behaves typical three stages, caused by the competition effect between work-hardening and dynamic-softening. The relationships between work-hardening rate and true strain and true stress were derived from Kocks-Mecking dislocation relation. The work-hardening effect shows two obvious stages with strain, viz. steady fluctuations and linear decreasing. An obvious work-hardening effect was demonstrated under lower temperature and higher strain rate. The linear relationship of work-hardening rate θ on true stress ε was constructed with the slope only related to annihilation coefficient Ω. The microstructural mechanism of as-cast GH4720Li superalloys during moderate-speed deformation was referred to dislocation multiplication and dendrite fragmentation, and the latter was beneficial to dynamic recrystallization during moderate-speed deformation.
Original languageEnglish
Pages (from-to)187-193
Number of pages7
JournalMaterials Science and Engineering A
Volume642
DOIs
Publication statusPublished - 6 Aug 2015

Keywords

  • Dislocation
  • Dynamic-softening (DS)
  • GH4720Li superalloys
  • Hot deformation
  • Microstructural mechanism
  • Work-hardening (WH)

ASJC Scopus subject areas

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

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