HTGR用Ni基耐熱合金のクリープ・疲労/雰囲気相互作用の評価法に関する検討

概要

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High Temperature Gas-cooled Reactor (HTGR) systems should be designed based on the high temperature Structural strength design proce dures. On the development of design code, the determination of fallure criteria under cyclic loading and severe environmentsis one of the most important items. By using the previous experimental data for Ni-base wrought alloys. Inconel 617 and Hastelloy XR, several evaluation methods for creep-fatigue interaction were examined for their capability to predict their cyclic loading behavior for HTGR application. At first, the strainrange partitioning method, the frequency modified damage function and the linear damage summation rule were discussed. However, these methods were not satisfactory with the above experimental results. Thus, in this paper, a new fracture criterion, which is a modification of the linear damage summation rule, is proposed based on the experimental data. In this criterion, fracture is conside-red to occur when the sum of the fatigue damage, which is the function of the applied cyclic strain magnitude, and the modified creep damage, which is the function of the applied cyclic stress magnitude (determined as time devided by cyclic creep rupture time reflecting difference of creep damages by tensile creep and compressive creep), reaches a constant value. This criterion was successfully applied to the life prediction of materials at HTGR temperatures.
社団法人日本材料学会の論文
1986-03-15