The role of grain boundaries on fatigue crack initiation - An energy approach

Michael D. Sangid, Hans J. Maier, Huseyin Sehitoglu

Research output: Contribution to journalArticlepeer-review


In this paper, we construct a model for prediction of fatigue crack initiation based on the material's microstructure. In order to do so, the energy of a persistent slip band (PSB) is monitored and an energy balance approach is taken, in which cracks initiate and the material fails due to stress concentration from a PSB (with respect to dislocation motion). These PSBs are able to traverse low-angle grain boundaries (GB), thus belonging to clusters of grains. As a consequence of the ongoing cyclic slip process, the PSBs evolve and interact with high-angle GBs, the result of which leads to dislocation pile-ups, static extrusions in the form of ledges/steps at the GB, stress concentration, and ultimately crack initiation. Hence, this fatigue model is driven by the microstructure, i.e. grain orientations, widely distributed grain sizes, precipitates, PSB-GB interactions, as well as the affect of neighboring grains. The results predict that cracks initiate near twin boundaries from PSBs spanning a single large grain with a favorable orientation or multiple grains connected by low-angle GBs. Excellent agreement is shown between model predictions and experimental data.

Original languageEnglish (US)
Pages (from-to)801-821
Number of pages21
JournalInternational journal of plasticity
Issue number5
StatePublished - May 2011


  • Energy methods
  • Fatigue
  • Grain boundaries
  • Persistent slip bands
  • Polycrystalline material

ASJC Scopus subject areas

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


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