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Prediction of Fatigue Lives of MAR-M247 LC Based on the Crack Closure Concept

Authors

  • Domnin Gelmedin,

    Corresponding author
    1. Karlsruhe Institute of Technology, Institute for Applied Materials – Materials Science and Engineering (IAM-WK) Campus Süd, Engelbert-Arnold-Straße 4, 76131 Karlsruhe, Germany
    • Karlsruhe Institute of Technology, Institute for Applied Materials – Materials Science and Engineering (IAM-WK) Campus Süd, Engelbert-Arnold-Straße 4, 76131 Karlsruhe, Germany.
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  • Karl-Heinz Lang,

    1. Karlsruhe Institute of Technology, Institute for Applied Materials – Materials Science and Engineering (IAM-WK) Campus Süd, Engelbert-Arnold-Straße 4, 76131 Karlsruhe, Germany
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  • James C. Newman Jr.

    1. Department of Aerospace Engineering, Mississippi State University, 314C Walker Engineering Building P. O. Box A Mississippi State, MS 39762, USA
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  • The financial support of the Bundesministerium für Wirtschaft und Technologie (BMWi) through the Arbeitsgemeinschaft industrieller Forschungsvereinigungen e.V. (AiF), (AiF-No. 14245 N), and the Forschungsvereinigung Verbrennungskraftmaschinen e.V. (FVV-No. 867) is gratefully acknowledged. Also thanks to Alstom Power Service, Siemens Power Generation Group, MTU Aero Engines, MAN Turbo, MAN B&W Diesel, and Rolls-Royce Deutschland for financing the material. Special thanks to the Karlsruhe House of Young Scientists (KHYS) which financially supported the stay abroad at the Mississippi State University (MSU). Cordial thanks to James C. Newman Jr. for the support during the visit at the Department of Aerospace Engineering at MSU.

Abstract

Low cycle fatigue (LCF), high cycle fatigue (HCF), and combined LCF and HCF tests are carried out on MAR-M247 LC at 650 °C in air environment. Under combined LCF and HCF loading, block striations form on the fracture surface which are used to complete an effective crack growth curve by using the linear summation model. Crack growth lives starting from equivalent initial flaw sizes are calculated by the crack closure code FASTRAN and compared with experimental fatigue lives. Under HCF loading, predicted and experimental fatigue lives agree well for lifetimes above 105 cycles. Lower lifetimes are overestimated indicating that the linear summation model is not valid for MAR-M247 LC in this loading range. Interactions between the non-crystallographic HCF crack growth and striated crack growth that is caused by the LCF loading are probably responsible for this behavior.

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