Finite element analysis of void growth behavior in nickel-based single crystal superalloys

Nonlinear stiffness method (NSM) was established to control the stress triaxiality. Based on the 3-D cell model, the void growth behavior in nickel-based single crystal superalloys (SXs) was analyzed with crystal plasticity theory and NSM. A range of factors were considered including stress triaxiality, initial volume fraction of voids, Lode parameters, crystallographic orientation, slip system activation and elastic anisotropy. The calculation results show that these factors influence the void growth character. The stress triaxiality is the driving force and plays an important role in void growth. At low stress triaxiality, the void deformation mainly exhibits as shape change, and at high stress triaxiality, it mainly exhibits as bulk expansion. The initial volume fraction of void influences the growth rate remarkably. The smaller the volume fraction is, the higher the growth rate is. The Lode parameter has great effect on the void growth and its shape change. The crystallographic orientation and activated slip systems have noticeable influence on the void growth, too. The void growth rate, when {1 1 1}〈1 1 0〉 slip system is activated, is higher than that when {1 1 1}〈1 1 2〉 slip system is activated. The elastic anisotropy plays an important role in void growth. The void grows faster in elastic isotropic matrix than that in elastic anisotropic matrix.