预应变对GH4169 合金低周疲劳行为的影响

为了研究发动机构件在实际工作中受到的轴向拉应力作用下疲劳行为的变化,开展了发动机常用材料GH4169合金在拉伸预应变条件下的低周疲劳行为的研究,得出疲劳寿命随预应变增加的变化规律。从宏观和微观2方面分析预变形对材料低周疲劳行为影响的变形机制。最终为解决实际工程中构件断裂等问题提供技术支持,同时也为评估航空发动机构件在产生预变形条件下的寿命,确保安全使用提供技术支撑。结果表明:随着预应变量的增加低周疲劳寿命降低,组织内位错密度、孪晶数量均增加,裂纹扩展长度减小。

Effect of Prestrain on Low Cycle Fatigue Behavior of GH4169 Alloy

In order to research the mechanical behaviors of aeroengine artifacts under the practical condition of tensile stress, the effect of prestrain on the fatigue behaviors of GH4169 alloy material which widely used in aeroengine was analyzed. The relation of the cycle life with increasing prestrain was obtained. The impact of prestrain on the deformation mechanism of GH4169 was investigated in-depth by both macrostructure and microstructure methods respectively. Technology sustainment was provided for the solution of fracture analysis of aeroengine artifacts and the security of aeroengine artifacts working in the prestrain condition. The results show that the cyclic number decreased with the increasing prestrain, the dislocation density and the number of twinning both increased with the increasing prestrain,while the length of extended crack reduced.