混合控制模式镍基合金蠕变变形研究

    Study on Creep Deformation of Nickel-based Alloy under Hybrid Control Mode

    • 摘要: 采用应力-应变混合控制(HCFI)试验方法,在650℃开展不同应变幅值、保载应力水平和保载时间下GH4169合金的蠕变-疲劳试验,研究其蠕变变形行为和蠕变-疲劳失效演变特征。结果表明:GH4169合金在HCFI试验应力保载期会持续产生蠕变变形,每周次的总蠕变量随着循环周次的增加不断增加,呈现三阶段的演化趋势。HCFI应力保载期的蠕变应变是区分于传统应变控制(SCFI)应力松弛的主要特征;同时HCFI加载能够灵活控制材料蠕变-疲劳失效过程中蠕变和疲劳损伤的比例,克服传统试验蠕变损伤易饱和的难题。

       

      Abstract: The stress-strain hybrid control(hybrid-controlled creep-fatigue interaction, HCFI)test method was adopted to carry out the creep-fatigue tests of GH4169 alloy under different strain amplitude, dwell stress level and dwell time at 650℃, and its creep deformation behavior and creep-fatigue failure evolution characteristics was studied. The results show that GH4169 alloy produce creep deformation continuously during the stress dwell period of HCFI loading. The total creep generated in each cycle increases with the increase of cycle, presenting three stages evolution trend. The creep strain during the stress dwell period of HCFI loading is the main feature which is different from the stress relaxation of the traditional strain control(SCFI), the loading method can also control the proportion of creep and fatigue damage in the process of creep-fatigue failure of materials and overcome the problem of creep damage saturation in traditional tests.

       

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