Twin boundary fatigue crack nucleation in a polycrystalline Nickel superalloy containing non-metallic inclusions

Non-metallic inclusions and twin boundaries are preferred fatigue crack nucleation locations in polycrystalline Ni-based superalloys. A Heaviside HR-DIC, EBSD multi-scale modelling strategy (CPFE-DDP) was used to assess experimental observations of near agglomerated RR1000 at elevated temperature. Inclusion fracture decohesion were observed within the first cycle loading. Fatigue non-metallic inclusion coincided with that an adjacent coarse grain containing a boundary. DDP boundary showed establishment slip activation parallel as well oblique interface, DIC characterisation. The results pile-up driven generation local GND density turn driving high stored energy nucleation. These conditions shown result from anisotropic elastic constraint In addition, complex stress field arising agglomerate drives plasticity contributing necessary for