The creep and fracture characteristics of a Ni‐based superalloy with preprecipitated δ phases are researched at the intermediate temperatures (630–670 °C). The influences of external stress and temperature on the creep properties and rupture mechanisms are analyzed. It is observed that the creep rupture time decreases, whereas the minimum creep rate increases, as the creep temperature or external stress is raised. With raising the external stress, the failure pattern changes from the mixed intergranular/transgranular mode to the intergranular fracture. A Monkman–Grant (MG) model is established to characterize the relationship between the residual creep life and experimental parameters (external stress and temperature). The small error between the forecasted and measured residual creep life verifies that the established MG model can be applied to evaluate the creep life of the studied superalloy.

中文翻译：

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中间温度下具有δ相的镍基高温合金的蠕变特性和断裂机理

在中间温度（630–670°C）下研究了具有沉淀δ相的镍基高温合金的蠕变和断裂特性。分析了外部应力和温度对蠕变性能和断裂机理的影响。观察到，随着蠕变温度或外应力的升高，蠕变断裂时间减少，而最小蠕变速率增加。随着外部应力的增加，破坏模式从晶间/经晶混合模式转变为晶间断裂。建立Monkman-Grant（MG）模型来表征残余蠕变寿命与实验参数（外部应力和温度）之间的关系。