Thermo-Mechanical Fatigue Crack Growth and Phase Angle Effects in Ti6246

A bespoke TMF crack growth test set-up has been developed and validated for use throughout this study and the effects of phasing between mechanical loading and temperature have been investigated. The study shows that TMF cycles may show increased crack growth rate behaviour when compared to isothermal fatigue. The phase angle of the applied TMF cycle can also affect crack growth behaviour, with in-phase (IP) test conditions showing faster crack growth rates than out-of-phase (OP) test conditions. Propagating cracks interact with the microstructure of the material, in particular, the alpha/beta interfaces within the prior beta grains and supporting fractography evidences subtle differences in fracture mechanisms as a result of phase angle.

Automated summary

A bespoke TMF crack growth test set-up was developed and validated for this study, and the effects of phasing between mechanical loading and temperature were investigated. The study revealed that TMF cycles may exhibit increased crack growth rate behavior compared to isothermal fatigue. The phase angle of the applied TMF cycle also influenced crack growth behavior, with in-phase (IP) conditions showing faster crack growth rates than out-of-phase (OP) conditions. Propagating cracks interacted with the microstructure of the material, particularly the alpha/beta interfaces within the prior beta grains, and supporting fractography demonstrated subtle differences in fracture mechanisms due to phase angle.