Investigation on fatigue threshold testing methods in a near lamellar TiAl alloy

Shiyuan Wang, Hangyue Li*, Paul Bowen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The effects of influential fatigue testing factors, including loading schemes (e.g., traditional load shedding and staircase load increasing), morphology of crack starters, and precracking approaches on the near-threshold fatigue crack growth behaviors for a near lamellar γ-TiAl alloy (Ti-45Al-2Mn-2Nb-1B) were investigated at room temperature and 650°C. The results showed that the measured fatigue threshold values in lamellar -TiAl alloys are very sensitive to the applied testing procedures. For example, the staircase load-increasing method yielded smaller threshold values. When such a load-increasing method was used, the threshold values were measured either from a notch machined by electro-discharge machining or prepared by a compression-compression fatigue loading. Moreover, some differences could be seen with respect to the morphologies of the crack starters. Most of the above influences are associated with the brittle nature of the material and the characteristics of the lamellar microstructures, and closure effects are primarily induced by crack wake roughness or unbroken ligaments.

Original languageEnglish
Issue number21
Publication statusPublished - 1 Nov 2019

Bibliographical note

Funding Information:
This work was conducted at the University of Birmingham, UK. In addition, the author would like to give special thanks to Chatuporn Po-Sri for assistance with data generation. This research received no external funding.

Publisher Copyright:
© 2019 by the authors.


  • Fatigue crack growth
  • Fatigue crack threshold
  • Fatigue testing method
  • Load-increasing method
  • Near lamellar γ-TiAl alloy

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics


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