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本文研究了迭加压应力过载峰S_P的时间间隔△t对镍基高温合金GH 698在700℃下疲劳蠕变交互作用的影响.结果表明,随着△t的逐渐减小,加剧合金的疲劳损伤,扩大了断口上疲劳断裂模式的范围,抑制沿晶蠕变断裂模式,这种变化对断裂寿命有明显影响.与此同时,迭加S_P对动态蠕变速率ε及疲劳裂纹扩展速率dα/dN的影响均表现为正反两个方面.当△t较短时,加速动态蠕变与裂纹扩展的因素起主导作用,导致寿命缩短;当△t较长时,则反之.
In this paper, the influence of superimposed stress overload peak S_P time interval Δt on the fatigue-creep interaction of Ni-based superalloy GH 698 at 700 ℃ is studied. The results show that with the gradual decrease of △ t, the fatigue of the alloy is aggravated Damage, expanding the scope of the fatigue fracture mode on the fracture, inhibiting the creep rupture mode, which has a significant effect on the fracture life.At the same time, the superposition of S_P on dynamic creep rate ε and fatigue crack growth rate dα / The influence of dN both positive and negative.When △ t is short, accelerating dynamic creep and crack growth play a leading role in the factors leading to shortened life expectancy;