Crystal plasticity modeling of local deformation behavior of Ni-based single-crystal superalloy turbine blade fir tree

A crystal plasticity model incorporating anisotropic elasticity and slip-based viscoplasticity was developed to investigate local deformation in Ni-based single-crystal superalloy turbine blade fir-tree roots. The proposed model captures the activation of both { 111 } < 110 > and { 111 } < 112 > slip systems through < 110 > − < 112 > dislocation reactions. Compared to the isotropic elastic–plastic model, the crystal plasticity model predicted significantly higher local fields at the edge of the contact region, with a 16.4 % higher peak equivalent stress (1109 MPa) and a 5.3 % greater peak equivalent strain (0.02). These differences are attributed to two mechanisms uniquely captured by the crystal plasticity model: (1) local elastic stiffening due to a shift in the principal stress direction from < 001 > to < 111 > under multiaxial loading and (2) accelerated shear accumulation driven by dislocation reactions. These results underscore the importance of using micromechanism-based models to assess the structural integrity of Ni-based single-crystal superalloy turbine blades. ● Developed anisotropic elasto-viscoplastic crystal plasticity model for Ni-based single crystal superalloys. ● Model uses <110>-<112> dislocation reactions and {111}<110>/{111}<112> slip systems for anisotropic deformation prediction. ● CP-FEM simulations show 16.4 % higher stress and 5.3 % larger strain at edge of contact vs. isotropic model. ● Multiaxial stresses at the edge of contact cause elastic stiffening and accelerated shear accumulation. ● Model supports structural integrity evaluation of turbine blade fir tree by capturing anisotropic deformation.