Fatigue life evaluation of a single crystal Ni-base superalloy, accompanying with change of microstructural morphology

✍ Scribed by Motoki Sakaguchi; Masakazu Okazaki

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 333 KB
• Volume: 29
• Category: Article
• ISSN: 0142-1123
• DOI: 10.1016/j.ijfatigue.2006.12.018

✦ Synopsis

A new micromechanics model was proposed to estimate the effects of microstructural geometry on fatigue life of single crystal Ni-base superalloys. The Eshelby's theory, the averaging field approximation and the hybrid composite theory were combined and extended so that it makes possible to discuss many types of microstructural factors: volume fraction of c 0 precipitates, c/c 0 lattice misfit, and inhomogeneities between c/c 0 phases against elastic or plastic deformation. The presented method can be applied to such a material system in which the c/c 0 morphology is changed during the cyclic loading at high temperature. The numerical calculations demonstrated that the plate-type rafted structure perpendicular to uni-axial stress direction may have detrimental effect on the isothermal fatigue strength for negative misfit superalloys.