College Park, Maryland June 6 - 10 , 2004
MP32: Development of Internal Strains During the Fatigue of Haynes 230 Nickel Based Superalloy
T. A. Saleh, M. L. Benson (Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996, USA.), H. Choo (Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA.; Metals and Ceramics Division, Oak Ridge National Laboratory), D. W. Brown (Los Alamos Neutron Science Center, Los Alamos National Laboratory), P.K. Liaw, R. A. Buchanan (Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA.), D. L . Klarstrom (Haynes International, Inc., Kokomo, IN 46904, USA.), D.G. Park (Korea Atomic Energy Research Institute, Yuseong P.O. Box 105, Daejeon, 305-600, Korea)
Haynes 230 is a solid solution strengthened, FCC, nickel based superalloy. This alloy is commonly used in flying and land-based turbines, and in other fatigue intensive applications. In situ neutron diffraction was used to investigate the behavior of internal strains in this alloy under both strain-controlled tension/compression, and stress-controlled tension/tension fatigue conditions. Experiments took place at the Spectrometer for Materials Research at Temperature and Stress (SMARTS) facility at the Los Alamos Neutron Science Center (LANSCE) and at the ENGIN-X spectrometer at ISIS. Residual strains were seen to develop and saturate during the first 100 fatigue cycles. Little, if any, strain relaxation was noted as 85 % of the fatigue life was reached. Characteristics of both in situ lattice strains and residual strains in various hkl directions during the fatigue deformation will be discussed in comparison to those observed during monotonic tensile testing.
Acknowledgements: The author acknowledges the financial support of the National Science Foundation, the Integrative Graduate Education and Research Training (IGERT) Program, under DGE-9987548, and the International Materials Institutes (IMI), under DMR-0231320, to the University of Tennessee, Knoxville, with Dr. W. Jennings, Dr. L. Goldberg, and Dr. C. Huber as contract monitors, respectively.
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