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Long-term Creep Strain-Time Curve Modeling of Alloy 617 for a VHTR Intermediate Heat Exchanger  

Kim, Woo-Gon (Nuclear Materials Research Division, Korea Atomic Energy Research Institute)
Yin, Song-Nam (Nuclear Materials Research Division, Korea Atomic Energy Research Institute)
Kim, Yong-Wan (Nuclear Materials Research Division, Korea Atomic Energy Research Institute)
Publication Information
Korean Journal of Metals and Materials / v.47, no.10, 2009 , pp. 613-620 More about this Journal
Abstract
The Kachanov-Rabotnov (K-R) creep model was proposed to accurately model the long-term creep curves above $10^5$ hours of Alloy 617. To this end, a series of creep data was obtained from creep tests conducted under different stress levels at $950^{\circ}C$. Using these data, the creep constants used in the K-R model and the modified K-R model were determined by a nonlinear least square fitting (NLSF) method, respectively. The K-R model yielded poor correspondence with the experimental curves, but the modified K-R model provided good agreement with the curves. Log-log plots of ${\varepsilon}^{\ast}$-stress and ${\varepsilon}^{\ast}$-time to rupture showed good linear relationships. Constants in the modified K-R model were obtained as ${\lambda}$=2.78, and $k=1.24$, and they showed behavior close to stress independency. Using these constants, long-term creep curves above $10^5$ hours obtained from short-term creep data can be modeled by implementing the modified K-R model.
Keywords
creep; creep curve; nonlinear least square fitting (NLSF); kachanov-rabotnov (K-R) model; Alloy 617;
Citations & Related Records
Times Cited By KSCI : 3  (Citation Analysis)
Times Cited By Web Of Science : 2  (Related Records In Web of Science)
Times Cited By SCOPUS : 2
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