Review: Creep-fatigue Interaction Testing and Damage Assessment for High Temperature Materials

In the field of high temperature material applications, the creep-fatigue interaction is a very important phenomenon that has to be taken into account during the design and life evaluation of critical components. In fact, creep and fatigue can affect each other reducing the expected endurance of high temperature components. The knowledge of the physical mechanisms that rule material behavior in these service conditions is fundamental for material scientists to improve existing materials. Nevertheless, the engineers have to be able to deal with this problem through new lifting procedures that comprehend this interaction. The possibility to comprise this phenomenon within design and lifting strategies is fundamental as the life prediction is more consistent with real operating regimes and does not jeopardize to have extremely conservative endurance evaluation. In the present article the creep-fatigue interaction in high temperature components is shortly summarized and the standardized life assessment procedure is presented. Finally, the creep-fatigue testing that help the definition of the damage assessment diagram are described.