Combined elastic-plastic energy driving criteria of rafting behavior for nickel-based single crystal superalloys

Abstract

The rafting of the microstructure of Nickel-based single crystal superalloys is related to the mechanics of the precipitated and matrix phases flowing together. Thus, based on the distribution of the driving force for two-phase movement, an elastic-plastic energy driving criteria of rafting behavior have been proposed to explain its mechanics and to predict the type of rafting. The microscopic cell finite element model that was developed introduced the rafting criteria to predict the morphology and type of rafting during creep under uniaxial tensile and compressive loads, respectively. The prediction is consistent with experimental observation. The results show that the drop in the interfacial dislocation energy density between the three <001> crystal directions affects the direction of the matrix phase movement, and the disturbance of the interfacial elastic strain energy changes the growth direction of the precipitated phase.