Quantification of the creep, fatigue, and oxidation damage and life prediction

Abstract

Materials at high temperatures may undergo damage due to the interaction of creep, fatigue, and oxidation. Since the last decade, many methods have been developed to predict the life of the materials under creep–fatigue interaction (CFI) loading. However, oxidation damage is very rarely considered in such prediction models. Moreover, most of the methods available in the literature use a lot of testing and data acquisition from pure fatigue, creep–fatigue, and pure creep tests. To overcome these difficulties, this article investigates the tensile hysteresis strain energy density method (THSED) available in the open literature. A modified THSED method that takes into account oxidation damage is proposed and implemented with four different materials for uniaxial CFI and hybrid CFI loading conditions. The proposed method could predict the CFI life of 304 SS, 304L SS, Mod. 9Cr-1Mo steel, and P92 steel within a scatter factor of ±2.0. The model parameter ( γ ), determined by the hit-and-trial method in the existing THSED method, is found to be dependent on the oxidation damage, strain rate, and hold time. The analytical expressions for the estimation of THSED for uniaxial and hybrid CFI loading conditions have also been derived.