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.
Effect of the interval (△t) of compressive overload peak (S_p) on thefatigue-creep interaction for GH698 alloy at 700℃ has been studied. It was foundthat, under the condition of superimposed S_p, the fatigue damage aggravates withthe decrease of △t, meanwhile, the fraction of fatigue fracture mode on fracturesurface was extended and that of intergranular creep fracture mode was supressed.The effect of superimposed S_p on both the dynamic creep rate ε and fatigue crackgrowth rate dα/dN depend upon the △t. As △t. was getting shorter, the factorwhich acceterates dynamic creep and crack propagation becomes dominant, this re-sults in the decrease of rupture life and vice versa.
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