Abstract
The effects of type II hot corrosion on the fatigue resistance of turbine blade superalloys is of growing interest as gas turbine (GT) original equipment manufacturers (OEMs) strive to optimise the operational efficiencies and versatilities of GT systems. Hot corrosion fatigue has been observed in the under platform regions of first stage GT blades, this location is subject to both relatively high principal stresses and stress gradients, combined with temperatures up to those associated with type II hot corrosion (500–700 °C). The effect of the deposition flux of corrosive salt species and the tensile stress dwell period on the fatigue performance and resultant crack morphologies of single crystal (SC) superalloy CMSX-4 has been studied at 550 °C. Deposit recoat methodologies were applied to specimens that were cyclically fatigued with a load-controlled trapezoidal waveform. It was observed that introducing a longer dwell period increased the number of {1 0 0} crack initiations and reduced the fatigue life (load cycles to failure). Optical and SEM microscopy and EDX techniques were used to examine specimen fractography, and mechanisms of crack advance and propagation discussed.
Highlights
Gas turbines (GTs) are used for a range of power generation applications; some of the more common being industrial power generation and aviation engines
The work presented in this paper focuses on type II hot corrosion and fatigue interactions, and studies the effect of extended dwell periods on fatigue life in the single crystal turbine blade alloy CMSX-4
For the 5 μg/cm2/h deposition flux curves a reduction in fatigue life of up to four times was observed with the introduction of a 60 s dwell period (Fig. 4)
Summary
Gas turbines (GTs) are used for a range of power generation applications; some of the more common being industrial power generation and aviation engines. One of the key limiting factors effecting the power density and thermal efficiencies that can be achieved by GTs is the operational gas temperatures reached in the turbine section of the engine. In addition to increasing temperatures the low cycle fatigue (LCF) duty cycles GTs are subjected to can be intensified as a result of increased multi start up and shut down procedures This can be as a result of increased renewables and peak loads on the energy grid in the case of industrial GTs, and increased short haul flights in the case of aviation engines. These combined factors provide the motivation for conducting combined hot corrosion fatigue testing
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
