Effect of microstructural features and their size on low cycle fatigue of CMSX-4® nickel base superalloy at high temperature

The low cycle fatigue behaviour of single crystalline samples made of nickel base superalloy has been investigated. Focus of the presentation is the effect of crystallographic orientation of the samples with respect to the loading direction and the effect of different thermal treatments on microstructure, damage evolution, and fatigue life. It was found that pores and defects play a major role when the the load is applied parallel to the direction of the cubic nickel base superalloy. Superior fatigue behaviour was found for single crystalline samples produced by selective electron beam melting (SEBM) which were further heat treated by hot isostatic pressing