Abstract:By means of X-ray diffraction analysis at different temperatures and microstructure observation, an investigation has been made on the influence of element Re and temperatures on the lattice parameter and the misfit of single-crystal nickel based superalloys. Results show that the bigger lattice parameter and misfit are displayed in as-cast superalloy. After fully heat treatment, the cubic g ￠ phase is coherently embedded in the g matrix phase, and the lattice parameters and misfit of g ￠ and g phases are slightly reduced. After aged for long time, the coarsening of g ￠ phase in the alloy occurs, and the interfacial dislocations appear between g ￠ and g phases, which increases the parameters and the absolute misfit of g ￠ and g phases. The lattice parameters of g ￠ and g phases in the alloys at room temperature increase with the element Re increasing, and the absolute values of the misfit decrease. Compared with the g ￠ phase, the g matrix phase displays a bigger dilation coefficient; therefore, the lattice parameters and the absolute misfit value of g ' and g phases in the alloy increase with the temperature increasing