Dynamic friction stresses in the γ phase of a nickel-based superalloy

Abstract In-situ deformation experiments were performed on single crystals of the short-range-order-containing γ phase of a nickel-based superalloy. The dislocation pile-ups moving under stress are used as a probe exploring this complex solid solution and giving precise information on the local glide resistance encountered. Their analysis gives access for the first time to several contributions to this glide resistance. The threshold friction stress, which pile-ups must overcome in order to move is equal to the dynamic friction stress, which the pile-up experiences when propagating at a constant velocity. In comparison, the glide resistances deduced from the analysis of relaxed configurations are shown to be significantly underestimated. The softening effect due to the destruction of short-range order is also quantitatively determined.