Microstructural simulations of the initiation and propagation of short fretting cracks in a Ti–6Al–4V contact

• Ti–6Al–4V fretting crack initiation and propagation model.
• Crystal plasticity constitutive behaviour.
• Realistic mesh build from EBSD observations.
• Crack propagation achieved through remeshing.
• Crack growth rates in individual grains can be evaluated.

Fretting–fatigue contact has been identified as a serious actor in damaging plane engines turbine discs. It has been the subject of many studies but remains partly misunderstood especially within the initiation and growth of short cracks in the Ti–6Al–4V microstructure. Although there is microstructural effect due to the existence of grain orientations and boundaries these cracking processes are generally not modelled. In this study, a two dimensional numerical model of fretting contact based on the finite elements method is developed to simulate and reproduce the crack growth within a real Ti–6Al–4V microstructure observed by Electron Back Scattered Diffraction. This model, using constitutive relations such as crystal plasticity, is able to assess the cracking speed corresponding to the crack growth crossing the very first grains. This study brings up a new scale in the fretting life time description taking into account a real Ti–6Al–4V complex metallic microstructure.