Damage evolution and life modeling of hot corrosion environment on creep‐fatigue of a directionally solidified nickel‐based superalloy

Abstract

This study developed a corrosion‐creep fatigue‐life‐prediction methodology based on continuous‐damage mechanics (CDM). A systematic investigation of the turbine‐blade material DZ125 (a nickel‐based superalloy) was conducted, including oxidation and high‐temperature hot corrosion‐creep fatigue tests. Pre‐exposure experiments explained the damage process in DZ125. The applicability of the CDM‐based life‐prediction model of DZ125 was verified experimentally and by comparison with corresponding data from published studies. The model exhibited excellent life‐prediction ability for gas‐turbine hot‐section components vulnerable to cyclic loads and hot corrosion combined.

Multiaxial creep–fatigue failure mechanism and life prediction of a turbine blade based on a unified numerical solution approach

“…Therefore, the creep-fatigue interaction is one of the main causes of the failure. [2][3][4][5][6][7][8][9][10][11][12] More specifically, the turbine blades are identified as the key structure that is highly susceptible to failure due to the multiaxial loading effect caused by the centrifugal and pneumatic forces under actual loading conditions. The actual loading condition generates the combination effect of bending and torsional loading, which has a significant effect on the creep-fatigue properties of Inconel 718 superalloy.…”

“…Such hot‐end components are usually subjected to complex alternating loading during start‐ups, operations, and shut‐downs, which will not only lead to inevitable fatigue damage but also cause creep damage after long‐term operation. Therefore, the creep–fatigue interaction is one of the main causes of the failure 2–12 . More specifically, the turbine blades are identified as the key structure that is highly susceptible to failure due to the multiaxial loading effect caused by the centrifugal and pneumatic forces under actual loading conditions.…”

High temperature creep fracture behavior of nickel-base single crystal superalloys

“…Therefore, investigating the creep resistance of single crystal alloys is of paramount importance [10][11][12]. Under high-temperature creep conditions, rapid degradation of the γ/γ' phase structure and the formation of a three-dimensional dislocation network are fundamental characteristics of their microstructural evolution [13][14][15][16][17]. It is commonly believed that dislocation cutting of the γ' phase rafting structure can lead to a decrease in creep resistance and an increase in creep rate.…”