Creep fracture parameters of functionally graded coating

Functionally graded coating (FGC) has been widely used in severe conditions for its excellent mechanical characteristics compared with pure coating material. The graded component in the FGC can be described by specified local volume fraction rules of coating material. In this paper an inhomogeneous finite element method is used to investigate the crack behavior in FGC at elevated temperature with the powerlaw constitutive equation. The path‐ independent integral value C* characterizes amplitude of the crack tip stress fields at steady stage. Different volume fractions of coating material, creep coefficients and creep indices are analyzed by systematic computation to obtain the effects of these factors on crack growth and obtain the knowledge to minimize crack damage in the FGC. In addition, strain energy density rate factor, ?, is proposed as a material parameter for measuring crack resistance capability in creep conditions. The preliminary analysis with ? is also applied in FGC and the numerical...