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本文研究了压应力过载峰(S_P)对GH698镍基高温合金700℃下疲劳蠕变交互作用的影响.S_P约在0至-400MPa范围时,断裂周次因存在S_P而增加.当S_P过大或过小时,断裂周次减小.动态蠕变速率的变化和断裂周次呈相反的对应关系.研究表明,S_P的作用表现在四个方面,即减小动态蠕变速率;促进疲劳损伤,引起断裂模式变化;延缓裂纹扩展和产生S_P本身的疲劳损伤.这些作用的强弱随基载循坏应力及S_P值的大小而异.
In this paper, the effect of compressive stress overload (S_P) on the fatigue-creep interaction of GH698 nickel-base superalloy at 700 ℃ is investigated. The fracture cycle increases with the presence of S_P when S_P is in the range of 0 to -400MPa. Or too small, the fracture weekly decreases.The change of dynamic creep rate is opposite to the fracture weekly.Research shows that the effect of S_P is manifested in four aspects, namely, reducing the dynamic creep rate, promoting the fatigue damage, Causing the change of the fracture mode, retarding the crack propagation and generating the fatigue damage of S_P itself.These effects depend on the magnitude of the cyclic stress and the value of S_P.