Slip analysis in a Ni-base superalloy

A Ni-base superalloy single crystal with γ/γ′ microstructure was tested in tension at room temperature along the 〈1 0 0〉, 〈1 1 0〉 and 〈1 1 1〉 directions and the evolution of the deformation bands was studied in these samples. It is demonstrated that the observation of the wavy deformation traces are associated with changes in the width of γ-channels and the falling off of the γ′-particles from the surface. The paths of the deformation bands were found to depend on the loading orientation and to be influenced by the probability of particle shearing as well as the relative orientation of the dendrites. At large strains where significant γ′-particle shearing occurs, the classical straight and thin slip bands along the {1 1 1} traces were observed. In this paper, the evolution of deformation bands are discussed in terms of plastic localization at microscopic and macroscopic levels and correlated with the non-Schmid effect and strain hardening rate in single crystal superalloys.