Short fatigue crack growth in an artificial-defect-containing nanostructured bainitic steel

For a full exploitation of novel steels in applications under mechanical cyclic loading, it is vital to understand the crack-microstructure interactions. In this work, the fatigue behaviour of a nanostructured bainitic steel in the short crack regime has been studied considering the structural integrity of the material and its polycrystalline nature. For that purpose, a specimen containing an artificial defect has been designed and manufactured, sub-jected to interrupted fatigue testing, and examined by crystallography-sensitive techniques. Results show that, depending on the loading conditions, different crystallographic boundaries can play an important role in the crack path and crack growth rate.