The influence of contacting Ni-based single-crystal superalloys on fretting fatigue of Ni-based polycrystalline superalloys at high temperature

Fretting fatigue tests at high temperature were carried out with single-crystal and polycrystalline alloys. The influence of the crystallographic orientation of contacting single-crystal pads on the lives of polycrystalline specimens is investigated. An analytical formulation of the contact problem between two anisotropic cylinders is used to study the changes in peak stress and contact width due to the orientation of the single-crystal. Finite element analysis is also used to study the variation of stress near the contact edge due to crystallographic orientation. An area averaging method is suggested to correlate fretting fatigue and plain fatigue curves. Using finite element analysis combined with the area averaging method, a better correlation was found between fretting fatigue results and plain fatigue.