Effect of grain size on mechanical properties of single phase Co-Ni-Cr-Mo based superalloy

Jun Kyung Sung, Mok Soon Kim, Won Yong Kim, Akihiko Chiba

Research output: Contribution to journalConference articlepeer-review

2 Citations (Scopus)

Abstract

A recrystallized Co-Ni-Cr-Mo based superalloy was produced by cold working of 72% and subsequent recrystallization heat treatment. Microstructural observation revealed that a full recrystallization of the cold-worked alloy occured when heat treatment was performed at and above 1273K for 1h. So that, recrystallization heat treatment was carried out in a temperature range from 1273K to 1473K for 1h-24h, by which the average grain size was controlled to 28μm-238μm. Tensile tests were carried out from room temperature (RT) to 1073K in order to understand the effect of grain size on the mechanical properties of the Co-Ni-Cr-Mo based superalloy. At RT and 943K, yield strength, tensile strength and elongation of the recrystallized alloy were improved with decreasing grain size. The alloy having a grain size less than 42μm exhibited a steady-state flow behavior in the true stress-true strain curve at 943K. However, the alloy having a grain size of 28μm showed lower yield strength than that of 42μm at 1073K. It was found that the steady state flow is closely related to the occurrence of {111}<112> deformation twinning in the Co-Ni-Cr-Mo based superalloy.

Original languageEnglish
Pages (from-to)631-634
Number of pages4
JournalMaterials Science Forum
Volume475-479
Issue numberI
DOIs
Publication statusPublished - 2005
Externally publishedYes
EventPRICM 5: The Fifth Pacific Rim International Conference on Advanced Materials and Processing - Beijing, China
Duration: 2004 Nov 22004 Nov 5

Keywords

  • Cobalt Based Alloy
  • Cold Working
  • Deformation Twinning
  • Mechanical Property
  • Recrystallization
  • Serrated Flow
  • Superalloy

ASJC Scopus subject areas

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

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