MULTI-SCALE DIFFRACTION STUDY OF REVERSIBLE/IRREVERSIBLE DEFORMATION MECHANISMS IN THE NI-BASED SUPERALLOYS DURING FATIGUE
- ORNL
- Argonne National Laboratory (ANL)
- University of Tennessee, Knoxville (UTK)
In this study, a nickel-based polycrystalline is subjected to cyclic loading. The subsequent fatigue damage has been investigated with in-situ neutron-diffraction, thermal characterization for a single-phase, transmission-electron microscopy (TEM) and polychromatic X-ray microdiffraction (PXM). Different stages of fatigue damage are observed including bulk hardening, softening, and eventual saturation evident in the diffraction patterns and the thermal-evolution features. An increase in dislocation density is responsible for hardening within the early cycles. The transition to saturation cycles is characterized by the anisotropy of the lattice-strain evolution. Inhomogeneity of the thermal response and irreversible compression of the lattice planes and statistical dislocation structures are observed in the final saturation fatigue cycles. Analysis of the PXM-Laue patterns reveals cyclically-deformed microstructure near the grain boundaries, which are composed of the lattice rotations and grain subdivisions. The PXM results are in good agreement with the TEM results. Combined simulation/experimental analysis allows determination of slip-system dependent dislocation density in individual grains.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 971592
- Resource Relation:
- Conference: Internation Symposium on Plasticity 2010, St. Kitts, St Kitts&Nevis, 20100103, 20100103
- Country of Publication:
- United States
- Language:
- English
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