Strain controlled low cycle fatigue behavior of U720Li disk superalloy above 700 °C

Fei Sun*, Yuefeng Gu, Kyoko Kawagishi, Hideyuki Murakami, Yoko Yamabe-Mitarai

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The low cycle fatigue behaviors of Udimet 720Li (U720Li) and the related microstructure evolution have been investigated at 725 °C under strain control tests. The interrelationships between microstructure factors and properties were analyzed using transmission electron backscatter diffraction (t-EBSD) in scanning electron microscopy (SEM) and transmission electron microscopy (TEM). For comparison, LCF behaviors at 650 °C were also presented to find the inferior aspects of U720Li alloy at relatively higher service temperatures. The results show that recrystallization occurs during the LCF testing at 725 °C. The extent of recrystallization increases with the strain. The LCF property at 725 °C is weakened to a large extent after recrystallization, which could be the significant factor that causes LCF degradation. Combination t-EBSD and TEM are beneficial for characterizing and analyzing the microstructure evolution in terms of primary y' precipitates and dislocations, proposing that gliding dislocations could concentrate into walls to form sub-grain boundaries, with the combination of primary y' precipitates to form sub-grains.

Original languageEnglish
Title of host publicationProceedings of the 9th International Symposium on Superalloy 718 and Derivatives
Subtitle of host publicationEnergy, Aerospace, and Industrial Applications
EditorsKarl Heck, Zhongnan Bi, Joel Andersson, Xingbo Liu, Kevin Bockenstedt, Chantal Sudbrack, Jon Groh, Eric Ott, Ian Dempster, Paul Jablonski, Daisuke Nagahama, Max Kaplan
PublisherSpringer International Publishing
Pages779-788
Number of pages10
ISBN (Electronic)9783319894799
DOIs
Publication statusPublished - 2018
Externally publishedYes
Event9th International Symposium on Superalloy 718 and Derivatives: Energy, Aerospace, and Industrial Applications - Pittsburgh, United States
Duration: 2018 Jun 32018 Jun 6

Publication series

NameMinerals, Metals and Materials Series
Volume2018-June
ISSN (Print)2367-1181
ISSN (Electronic)2367-1696

Conference

Conference9th International Symposium on Superalloy 718 and Derivatives: Energy, Aerospace, and Industrial Applications
Country/TerritoryUnited States
CityPittsburgh
Period18/6/318/6/6

Keywords

  • Disk superalloy
  • Low cycle fatigue
  • Microstructure transmission-EBSD
  • TEM
  • U720Li

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy Engineering and Power Technology
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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