Competing Modes for Crack Initiation from Non-metallic Inclusions and Intrinsic Microstructural Features During Fatigue in a Polycrystalline Nickel-Based Superalloy

Jean Charles Stinville, Etienne Martin, Mallikarjun Karadge, Shak Ismonov, Monica Soare, Tim Hanlon, Sairam Sundaram, McLean L.P. Echlin, Patrick G. Callahan, William C. Lenthe, Jiashi Miao, Andrew E. Wessman, Rebecca Finlay, Adrian Loghin, Judson Marte, Tresa M. Pollock

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Cyclic fatigue experiments in the high and very high cycle fatigue regimes have been performed on a René 88DT polycrystalline nickel-based superalloy. The microstructural configurations that favor early strain localization and fatigue crack initiation at high temperature from 400 °C to 650 °C have been investigated. Competing failure modes are observed in the high to the very high cycle fatigue regime. Fatigue cracks initiate from non-metallic inclusions and from intrinsic internal microstructural features. Interestingly, as stresses are reduced into the very high cycle regime, there is a transition to initiation only at crystallographic facets. At higher stress in the high cycle fatigue regime, a significant fraction of specimens initiate cracks at non-metallic inclusions. This transition is analyzed with regard to microstructural features that favor strain localization and accumulate damage early during cycling.

Original languageEnglish (US)
Pages (from-to)3865-3873
Number of pages9
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Volume49
Issue number9
DOIs
StatePublished - Sep 1 2018
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys

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