TEMin situstraining of the MC2 superalloy at room temperature

By deforming the Mc2 nickel-based superalloy at room temperature in a TEM, we were able to study the succession of mechanisms that control the movement of the dislocation through the channels of they phase, at the interfaces and on shearing of the γ′ precipitates. We demonstrated the occurrence of small pile-ups that locally multiply the stress and adapt it to the various sites of resistance within the material. The results led us to reconsider the relationships from the literature giving the critical propagation stresses in the channels of the matrix and crossing the interfaces. We were thus able to account for the dynamic observations made and, in particular, to predict the number of dislocations in the small pile-ups that allow various obstacles to be crossed.