A Mathematical Framework for Cyclic Life Prediction of Directionally Solidified Nickel Superalloys
Modern gas turbines utilize single crystal (SX) and directionally solidified (DS) nickel superalloys which hold a higher cyclic life resistance and an improved creep rupture strength compared to their conventionally cast (CC) version. Both, SX and DS materials feature a significant direction dependence of material properties, which needs to be considered in the constitutive and lifing models. In this context, the paper presents a mathematical framework of cyclic life prediction. Although the method is developed for DS nickel alloys with transverse isotropic material behaviour, a generalisation to common orthotropic materials inclu¬ding SX is straightforward. The proposed procedure is validated by two examples. Moreover, an application to turbine components is shown.
R. Mücke "A Mathematical Framework for Cyclic Life Prediction of Directionally Solidified Nickel Superalloys", Advanced Materials Research, Vol. 278, pp. 363-368, 2011