During in situ investigation of the distribution of lattice parameters within a superalloy with a rafted microstructure, using three-crystal diffractometry, both the γ and γ' peak positions and shapes were shown to change. While the peak positions could be used to measure the average stresses and strains within both phases, the changes in shape were related to these in the dislocation distribution within the material. It was shown that the density and order of the dislocation array at the γ/γ' interface and within the γ' phase gave different contributions to the peak width, and that the widening of both peaks under high stresses was due to an increase of the dislocation density within the rafts.

Strains and Dislocation Densities within a Rafted Superalloy: in situ Investigation during Mechanical Testing at 1080C. L.Dirand, A.Jacques, J.P.Chateau, T.Schenk, O.Ferry, P.Bastie: Journal of Physics - Conference Series, 2010, 240[1], 012080