Plate impact experiments and crystal plasticity finite element modeling of solution-treated Inconel 718 superalloy

Impact response of a solution-treated hot-rolled Inconel 718 superalloy is investigated with plate impact experiments and crystal plasticity finite element modeling. Free surface velocity measurements are conducted along with postmortem microstructure characterizations. The Hugoniot equation of state is determined up to 21 GPa. Dislocation slips, stacking faults and Lomer–Cottrell dislocation locks are predominant deformation mechanisms. A crystal plasticity model considering thermal activation and dislocation drag is developed to simulate shock compression and spallation of the superalloy. This constitutive model reproduces the measured free surface velocity histories. During shock compression, the contributions of 12 independent slip systems to plastic deformation are approximately equal, and plastic strain mainly concentrates at grain boundaries or annealing twin boundaries. There is an increase in the number of active slip systems at higher impact velocities. Simulations reveal both intergranular and intragranular micro-cracks at the primary stage of damage evolution, where intergranular cracks are predominant, consistent with experiments. The present research provides insights into and a useful modeling case for understanding high strain rate deformation and spallation of Inconel 718 superalloy.