Assessment of Shot-Peening on Fatigue Life of Inconel 718 Turbine Disk

Author:  Jean-Patrick Goulmy, V. Boyer, L. Toualbi, P. Kanoute, S. Kruch, D. Retraint, E. Rouhaud, A. Seror, Q. Puydt
Source:  ICSP-13
Doc ID:  2017046
Year of Publication:  2017
Abstract:  
Introduction: Surface enhancement methods, such as shot peening, are widely used in the aerospace industry to improve the fatigue life of critical components. Such processes generate residual compressive stresses which tend to delay fatigue crack initiation and prevent small crack propagation. However,these methods are efficient only if the thermo-mechanical relaxation of residual stresses at operating temperatures is moderate. As detailed in [1], the effect of work hardening is preponderant. There is a strong dependence of the degree of work hardening induced by creation of the compressive layer on the amount of relaxation during thermal loadings. Furthermore, work hardening is strongly related to the microstructure. The microstructural state of the component part before shot peening can then significantly modify the efficiency of this surface enhancement method and the fatigue life of the component.