Fatigue Crack Growth Resistance of Advanced Blade Materials

Abstract

The best measure of performance in a jet engine is the thrust-to-weight ratio. Cast single-crystal superalloys provide higher temperature capability and offer opportunities for significant improvements in future jet engine performance and durability. The highly anisotropic behavior of these advanced materials, which includes modulus, strength, and ductility variation with crystallographic orientation, pose potentially significant problems for design and life prediction of advanced turbine blades. The objective of this paper is to provide a better understanding of the crack growth behavior in this advanced turbine blade material by evaluating the effect of temperature, frequency, orientation, and thickness.

Crack growth in single crystal gas turbine blade alloys under service-like conditions

“…It has been observed, both in the present work and by other researchers [81][82][83][84][85][86][87][88][89][90][91][92][93][94][95][96][97][98] that crystallographic crack growth in single crystal nickel base superalloys is closely related to localized inelastic deformation along the {111} crystal planes. The dislocation motions that give rise to this inelastic deformation are driven by shear stresses on the {111} planes.…”

“…The isothermal fatigue crack growth behaviour of single crystal nickel base alloys has also been studied by other authors [94][95][96][97][98] .…”

Crack growth in single crystal nickel base superalloys under isothermal and thermomechanical fatigue

“…The crack growth behaviour of single crystal superalloys under isothermal conditions has been previously studied [65][66][67][68][69][70][71][72][73][74][75][76][77][78][79][80] , although uncertainties still remain regarding the phenomenon of crystallographic crack growth. The localization of inelastic deformation to {111} planes and crystallographic crack growth along these planes provides a major challenge in terms of test data evaluation and crack growth modelling for single crystal superalloys.…”