Fatigue Failure Characteristics of Single-Crystal Fe-3%Al Alloy

Mitsuhiro Okayasu, Keisuke Noda

Research output: Contribution to journalArticle

Abstract

To obtain a better understanding of the mechanical properties and failure characteristics of the single-crystal Fe-3%Al alloy (SC), tensile and fatigue properties of the SC and polycrystalline Fe-3%Al alloy (PC) have been investigated. The tensile strength and fracture strain for the SC samples were different depending on the loading direction, i.e., 〈111〉, 〈110〉 and 〈100〉, which could be explained by the Schmid factor. Fatigue strength for the SC samples was basically correlated with their tensile strength. Different fatigue properties were obtained for the PC sample, e.g., the high fatigue strength was obtained in the early fatigue stage, and significant reduction in the fatigue strength was appeared in the later fatigue stage, e.g., low endurance limit at 107 cycles. The reason for this was caused by the material brittleness due to the accumulated dislocation at the grain boundaries. Because the high ductile SC samples made severe plastic deformation ahead of the crack tip, the crack growth rate did not enhance even if the high stress intensity factor range was applied in Region II (da/dN versus ΔK). The crack growth rate dropped just before the final fracture. Effective stress intensity factor range was estimated using the crack closure model, but the crack growth rate is found to be affected strongly by the slip system of SC sample.

Original languageEnglish
Pages (from-to)5978-5987
Number of pages10
JournalJournal of Materials Engineering and Performance
Volume28
Issue number10
DOIs
Publication statusPublished - Oct 1 2019

Fingerprint

Single crystals
Fatigue of materials
Crack propagation
Stress intensity factors
Tensile strength
Crack closure
Brittleness
Dislocations (crystals)
Crack tips
Plastic deformation
Grain boundaries
Durability
Mechanical properties
Fatigue strength
Direction compound

Keywords

  • crack growth
  • failure characteristic
  • fatigue property
  • single crystal
  • steel

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Fatigue Failure Characteristics of Single-Crystal Fe-3%Al Alloy. / Okayasu, Mitsuhiro; Noda, Keisuke.

In: Journal of Materials Engineering and Performance, Vol. 28, No. 10, 01.10.2019, p. 5978-5987.

Research output: Contribution to journalArticle

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