Small fatigue crack growth in a high entropy alloy

Kai Suzuki, Motomichi Koyama, Hiroshi Noguchi

Research output: Contribution to journalConference articlepeer-review

4 Citations (Scopus)

Abstract

High-entropy alloys (HEAs) contain a large amount of solid solution elements. This implies that the high capability of solid solution strengthening is expected to increase the resistance to fatigue crack growth. Therefore, we investigated the characteristics of microstructurally small fatigue crack growth of an HEA. In particular, we focused on microstructural fatigue crack growth behavior and associated scatter in crack growth rates. In this study, we used an equiatomic Fe-20Cr-20Ni-20Mn-20Co HEA and an Fe-18Cr-14Ni stable austenitic stainless steel. Rotating bending fatigue tests were performed at ambient temperature using smooth round bar specimens. The fatigue limits of the HEA and stainless steel were 250 and 200 MPa, respectively. The higher fatigue limit of the HEA was attributed to the solid solution strengthening. Furthermore, the scatter in crack growth rates of the HEA was more significant than that of the stainless steel owing to the temporal deceleration or non-propagation of the crack. In the stainless steel, as the crack length increased, the scatter in crack growth rates decreased. In contrast, in the HEA, even if the crack length increased, the scatter in crack growth rates remained significant As a factor that is perhaps related to the scatter characteristics, fatigue cracks with a length of approximately 500 μm in the HEA were highly deflected, compared to those of the stainless steel.

Original languageEnglish
Pages (from-to)1065-1070
Number of pages6
JournalProcedia Structural Integrity
Volume13
DOIs
Publication statusPublished - 2018
Externally publishedYes
Event22nd European Conference on Fracture, ECF 2018 - Belgrade, Serbia
Duration: 2018 Aug 252018 Aug 26

Keywords

  • High-entropy alloys
  • Scatter in crack growth rates
  • Small fatigue crack growth

ASJC Scopus subject areas

  • Mechanical Engineering
  • Mechanics of Materials
  • Civil and Structural Engineering
  • Materials Science(all)

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