Cryogenic-temperature fracture toughness analysis of non-equi-atomic V10Cr10Fe45Co20Ni15 high-entropy alloy

Yong Hee Jo, Kyung Yeon Doh, Dong Geun Kim, Kwanho Lee, Dae Woong Kim, Hyokyung Sung, Seok S Sohn, Donghwa Lee, Hyoung Seop Kim, Byeong Joo Lee, Sunghak Lee

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4 Citations (Scopus)

Abstract

Representative face-centered-cubic (FCC) high-entropy alloys (HEAs) or medium-entropy alloys (MEAs), e.g., equi-atomic CoCrFeMnNi or CrCoNi alloys, have drawn many attentions due to the excellent damage-tolerance at cryogenic temperature. The investigation of fracture toughness at 77 K is basically required for the reliable evaluation of high-performance alloys used for cryogenic applications; however, it has been rarely carried out for the non-equi-atomic FCC HEAs yet. In this study, tensile and fracture toughness tests were conducted on the non-equi-atomic V10Cr10Fe45Co20Ni15 alloy, and the results were compared with those of the equi-atomic CoCrFeMnNi and CrCoNi alloys. The present alloy shows a good damage tolerance at cryogenic temperature with tensile strength of 1 GPa and elongation of ∼60%. The KJIc fracture toughness values are 219 and 232 MPa m1/2 at 298 and 77 K, respectively, showing the increase in toughness with decreasing temperature. This increase results from the absence of twins at 298 K and the increased propensity to twin formation at 77 K, which is well confirmed by the variation of stacking fault energies (SFEs) by using Ab-initio calculations. The mechanical properties of the present alloy are actually similar or slightly lower than those of the other CoNiCr or FeMnCoNiCr alloy; instead, this study provides that neither composition nor certain elements are the most important factors dictating damage-tolerance of HEAs or MEAs.

Original languageEnglish
Article number151864
JournalJournal of Alloys and Compounds
Volume809
DOIs
Publication statusPublished - 2019 Nov 15

Keywords

  • Ab-initio calculation
  • Cryogenic temperature
  • Fracture toughness
  • High-entropy alloy (HEA)
  • Stacking fault energy (SFE)

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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    Jo, Y. H., Doh, K. Y., Kim, D. G., Lee, K., Kim, D. W., Sung, H., Sohn, S. S., Lee, D., Kim, H. S., Lee, B. J., & Lee, S. (2019). Cryogenic-temperature fracture toughness analysis of non-equi-atomic V10Cr10Fe45Co20Ni15 high-entropy alloy. Journal of Alloys and Compounds, 809, [151864]. https://doi.org/10.1016/j.jallcom.2019.151864