Elevated temperature mechanical properties of Inconel 617 surface oxide using nanoindentation
- George Mason Univ., Fairfax, VA (United States); George Mason Univ., Fairfax, VA (United States)
- Texas A & M Univ., College Station, TX (United States)
- George Mason Univ., Fairfax, VA (United States)
Inconel 617 is a principal candidate material for helium gas cooled very-high-temperature reactors with outlet temperatures of 700–950 °C. Recent findings showed that this alloy develops unique surface oxide layers especially at high temperature (HT) helium environment with distinctive wear, friction and contact properties. This study investigates the elevated temperature mechanical properties of Inconel 617 top surface layers aged in HT helium environment. Nanoindentation technique is used to obtain load-displacement graphs of the alloy top surface oxide in temperatures ranging from 25 °C up to 600 °C. In addition, using finite element analysis along with an iterative regression technique, a semi-numerical method is developed to further measure and quantify the material parameters and, in particular, time-independent and creep characteristics of the oxide. Although Young's modulus of the oxide is found to be relatively close to the bulk for the tested temperatures, the yield strength and hardness, in comparison to the bulk material, increase significantly as the material is oxidized after aging. The oxide exhibits significant softening as the temperature increases to 600 °C. Unlike the bulk material, diffusion through the grains is found to be the dominant creep mechanism for the oxide. Considerable difference between the mechanical properties of the oxide and the bulk material shows the need for accurate measurements of near surface mechanical properties, if reliable predictive contact and tribological models are sought at elevated temperatures.
- Research Organization:
- Texas A & M Univ., College Station, TX (United States). Texas A & M Engineering Experiment Station
- Sponsoring Organization:
- USDOE Office of Nuclear Energy (NE)
- Grant/Contract Number:
- NE0008549
- OSTI ID:
- 1848151
- Alternate ID(s):
- OSTI ID: 1619908
- Journal Information:
- Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing, Journal Name: Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing Journal Issue: C Vol. 788; ISSN 0921-5093
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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