Interaction of thermally induced and mechanical fatigue

The influence of superimposed total strain controlled HCF loadings on TMF life is presented and discussed for several cast Al-Si alloys, the Ni-base superalloy Inconel 617 and the cast iron GJS-700. Except for GJS-700, a threshold of the superimposed HCF loading is observed, below of which TMF life is not significantly affected. The strong decrease of TMF life as soon as the HCF amplitude exceeds this threshold is due to fundamental changes in the crack propagation mechanisms. The paper closes with a brief overview on lifetime prediction methods for TMF and their application in the case of TMF/HCF loadings.