High temperature creep behavior of Inconel 617 and Haynes 230
The high temperature gas-cooled reactor (HTGR) has been selected for the Next Generation Nuclear Plant (NGNP) project. The structural materials of HTGR will serve in the temperature range of 760-950oC and withstand coolant pressure up to 7 MPa for a design life of 60 years. Currently, Ni-based Inconel 617 (Alloy 617) and Haynes 230 (Alloy 230) are considered to be the leading metallic candidate materials for applications in the HTGR due to their favorable mechanical properties at high temperatures. In the present study, focus is placed on the biaxial, long term, high temperature creep behavior for Alloy 617 and Alloy 230. The creep mechanisms, including dislocation creep and grain boundary sliding, were found for the stress range of 10 to 55 MPa at 850oC, 900oC and 950oC for Alloy 617. In the contrast, only dislocation creep was found for Alloy 230 at 850oC, different from the creep mechanism with both grain boundary sliding and dislocation creep at 900oC and 950oC. Both Alloy 617 and Alloy 230 have similar creep rupture lives at 950oC and 900oC, while Alloy 230 has a longer rupture life than Alloy 617 at 850oC. The equation ε= Aσ〖cosh〗^(-1) (1+rt)+Pσ^n t^m was used to simulate the creep curves for both alloys at temperatures of 850oC, 900oC, and 950oC. The simulation results have a reasonable agreement with experimental results at medium stress level, but overestimated the experimental result at low stress level and underestimated it at high stress level. The FEM simulation provides a better simulation result.
creep regimes, creep mechanism, creep simulation
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign