Friction stresses in the γ phase of a nickel-based superalloy

A method is proposed to evaluate the glide plane resistance tau(f) opposing the propagation of dislocation groups in a concentrated solid solution. The method is based on the measurement of the position of dislocations as observed in a relaxed pile-up. Two types of material have been investigated: single crystals of the gamma phase of the MC2 supernalloy and a model alloy of this phase especially designed for this study. At 500 degrees C, tau(f) (which in fact exceeds the yield stress tau(y)) stems from the contributions of solid solution hardening and, more important, of the ordering which takes place in these materials. The contributions from short-range and long-range order can be distinguished.